-
What gram staining is streptococcus
Gram + coccus
-
How does growth of strep and staph differ?
- Staph ? clusters of gram + cocci
- Strep ? gram + cocci grow along a single axis in pairs or long chains
-
What are group A strep
Strep pyogenes
-
What is the capsule of strep pyogenes made of?
Hyaluronic acid
-
What is special about hyaluronic acid capsule
- Hyaluronic acid is also found in our connective tissue
- Therefore, it is non immunogenic
-
What kind of hemolysis does strep pyogenes have?
Beta hemolytic
-
What kinds of infections can strep pyogenes cause?
- Pyogenic infections
- Toxin mediated
-
What pyogenic infections can strep pyogenes cause
- Impetigo
- Pharyngitis (strep throat)
- Cellulitis and erysipelas
-
What does impetigo look like?
Skin infection that looks honey crusted
-
What bacteria can cause impetigo
- Staph aureus
- Strep pyogenes
-
What does strep throat look like?
Red erythematous and inflamed throat
-
What is erysipelas
Superficial cellulitis with well demarcated borders
-
What is the most common cause of erysipelas?
Strep pyogenes
-
What toxin does strep pyogenes produce
- Streptococcal pyrogenic exotoxin (SPE)
- Streptolysin O
- Streptokinase
- DNases
-
what virulence factor mediates the beta hemolysis of strep pyogenes
streptolysin O ? lyses red blood cells
-
what antibodies do we create against strep pyogenes?
ASO ? Anti Streptolysin O antibodies
-
What does kinase mean
To add a phosphate
-
What does streptokinase do
- Converts plasminogen --> plasmin
- Plasmin is fibrinolytic (lyses clots)
-
What can we use streptokinase for in a medical medium?
To lyse clots in MI or ischemic strokes
-
What do DNases / Dornases do
Depolymerize DNA
-
How do we differentiate group A strep form Group B strep?
- Group A strep ? Bacitracin sensitive
- Group B strep ? Bacitracin resistant
-
How do we check if we have recently had a strep infection?
ASO antibody titers
-
What infections does streptococcal pyrogenic exotoxin cause
- Scarlet fever
- Toxic shock like syndrome
- Necrotizing fasciitis
-
What are the main symptoms of scarlet fever?
- Strawberry tongue ? reddening and swelling of tongue
- Pharyngitis
- Widespread rash that spares the face
-
What kind of toxins are pyrogenic exotoxin A and C and how does they work?
- Super antigen
- Causes nonspecific binding of MHC class 2 and T cell receptors --> over activation --> cytokine storm
- Could be fatal
-
What kind of toxin is pyrogenic exotoxin B?
Protease
-
What types of pyrogenic exotoxin exists?
- A ? super antigen
- B ? protease
- C ? super antigen
-
Which types of pyrogenic exotoxins are responsible for toxic shock like syndrome
A and C
-
Which types of pyrogenic exotoxins are responsible for scarlet fever
A and C
-
Which types of pyrogenic exotoxin are responsible for necrotizing fasciitis
B
-
What causes necrotizing fasciitis
Toxigenic strains of strep pyogenes
-
how does necrotizing fasciitis spread?
- invades the fascia underlying the skin
- spreads very rapidly
-
how do you treat necrotizing fasciitis?
- it is a true surgical emergency
- it is sometimes necessary to amputate the affected region
-
how do you treat strep infections?
penicillin
-
what are the serious complications of infections with strep pyogenes?
- Rheumatic Fever
- Post Streptococcal Glomerular Nephritis
-
What is the main virulence factor responsible for rheumatic fever?
M protein
-
What is M protein
Highly antigenic protein in strep pyogenes cell wall
-
How does M protein act as a virulence factor?
- Interferes with opsonisation ? anti-phagocytic
- Very antigenic ? elicits strong humoral response
-
What antigen resembles M protein
Self-antigen ? myosin in cardiac muscle
-
Through which process does M protein resemble myosin of the cardiac muscle
Molecular mimicry
-
What is the consequence of molecular mimicry in strep pyogenes infection?
Causes our own antibodies to attack our heart
-
Which valve is most commonly affected by rheumatic fever
Mitral valve
-
What problems does rheumatic fever cause for heart valves
Mitral stenosis
-
What disease does rheumatic fever occur after?
- Strep pharyngitis
- Never after skin infections
- Does not happen if pharyngitis is promptly treated
-
Who does rheumatic fever most commonly affect
Children who do not have access to good medical attention (the pharyngitis is not promptly treated)
-
What are the symptoms of rheumatic fever?
- J ? Joint ? polyarthritis
- <3 ? Heart ? valvular damage leading to murmurs, myocarditis, pericarditis
- N ? Nodules ? subcutaneous nodules that appear on extensor surfaces of forearms or elbows / knees
- E ? Erythema Marginatum ? rash with thick red borders
- S ? Sydenham?s Chorea ? rapid involuntary movements of hands and face
-
What are the Jones criteria?
- J ? Joint ? polyarthritis
- <3 ? Heart ? valvular damage leading to murmurs, myocarditis, pericarditis
- N ? Nodules ? subcutaneous nodules that appear on extensor surfaces of forearms or elbows / knees
- E ? Erythema Marginatum ? rash with thick red borders
- S ? Sydenham?s Chorea ? rapid involuntary movements of hands and face
-
What are the difference between rheumatic fever and post strep glomerulonephritis?
- Rheumatic fever
- type 2 hypersensitivity
- only after pharyngitis
- early diagnosis + treatment of pharyngitis can prevent development
- Post strep glomerulonephritis
- type 3 hypersensitivity
- occurs after pharyngitis or superficial infection (e.g. impetigo)
- early diagnosis + treatment of infection will not prevent development
-
How does strep pyogenes cause post strep glomerular nephritis?
- Type 3 hypersensitivity reaction
- Damage is mediated by circulating antibody ? antigen immune complexes that eventually deposit in the glomerulus
-
What are the main symptoms of post strep glomerular nephritis?
- Dark brown / cola colored urine
- Fascial swelling / puffiness from edema
-
How long does it take to develop post strep glomerular nephritis?
2 weeks after the initial strep infection
-
what diseases does post strep glomerular nephritis occur after
- pharyngitis
- superficial infections (e.g. impetigo)
-
how do you prevent post strep glomerular nephritis?
you can?t ? even when strep infection is treated promptly with penicillin this complication can still occur
-
What are the hemolytic properties of strep pneumoniae?
Alpha hemolytic
-
What does alpha hemolysis look like?
Surrounding zone of hemolysis is a green hue
-
Why is alpha hemolytic zone green
Due to oxidation of hemoglobin
-
What is strep pneumoniae capsule made of
Polysaccharide
-
What are the virulence factors of strep pneumoniae?
- Polysaccharide capsule
- IgA protease
-
What does IgA protease allow strep pneumoniae to do?
Colonies and invade mucosa
-
What does the capsule allow strep pneumoniae to do?
Evade immune system
-
How do you differentiate between strep pneumoniae and strep viridans?
- Strep pneumoniae
- optochin sensitive
- bile soluble (can?t grow in bile)
- encapsulated
- Strep viridans
- optochin resistant
- bile insoluble (grows on bile)
- unencapsulated
-
What shape is strep pneumoniae under high power microscopy
Lancet shaped gram + diplococci
-
What gram staining does strep pneumoniae have
Gram + coccus
-
Why can strep pneumoniae not grow on bile
It is bile soluble
-
What infections do strep pneumoniae cause
- M ? Meningitis
- O ? Otitis Media
- P ? Pneumonia
- S ? Sinusitis
-
What does MOPS stand for
- Infections for which strep pneumoniae is the most common cause
- M ? Meningitis
- O ? Otitis Media
- P ? Pneumonia
- S ? Sinusitis
-
What is the most common cause of community acquired pneumonia in adults?
Strep pneumoniae
-
What characteristic pneumonia does strep pneumoniae cause?
- Lobar pneumonia that infiltrates the lower lobes
- Causes rust colored sputum
-
Which population is at higher risk of being infected by encapsulated organisms
People who have undergone splenectomy or auto-splenectomy (e.g. in sickle cell disease)
-
Where are encapsulated organisms removed from the body
Spleen
-
How do we treat strep pneumoniae infection?
- Susceptible to Macrolides ? erythromycin
- 3rd generation cephalosporin ? ceftriaxone
-
How can we prevent strep pneumoniae infection?
2 pneumococcal vaccines available
-
How does the adult strep pneumoniae vaccine work?
- 23 valent polysaccharide vaccine
- T cell independent response generated
- This only creates IgM
- Not long lasting reaction
-
How does the child strep pneumoniae vaccine work?
- 7 valent conjugated to a protein
- Protein means it is more antigenic
- More robust T cell response
- IgG production
-
What are group B strep?
Strep agalactiae
-
Which group of people does strep agalactiae cause serious infections in
Newborns
-
What does hippurate in strep agalactiae do
Hydrolysis sodium hippurate
-
What is strep agalactiae?s capsule made of
Polysaccharide
-
How do we distinguish strep agalactiae from all other streps?
CAMP test
-
What is the CAMP test?
- When strep agalactiae is plated with staph aureus there is an increased zone of hemolysis
- Butterfly hemolytic zone
-
What are strep agalactiae hemolytic properties
Beta hemolytic
-
How do we differentiate strep pyogenes and strep agalactiae from strep pneumoniae and strep viridans?
- Strep agalactiae + strep pyogenes ? beta hemolytic
- Strep pneumoniae + step viridans ? alpha hemolytic
-
How do we differentiate strep agalactiae from strep pyogenes?
- Strep agalactiae ? bacitracin resistant
- Strep pyogenes ? bacitracin sensitive
-
What infections does strep agalactiae cause
- Meningitis in neonates
- Sepsis in neonates
- Pneumonia
-
What is the main cause of meningitis in neonates?
Strep agalactiae
-
How do neonates get strep agalactiae infections?
When the neonate passes through the vaginal canal of the mother during delivery
-
What prenatal care do we have to prevent neonatal strep agalactiae infections
Swab vagina and rectum of mother at 35 weeks to see if she is colonized
-
If mother is colonized with strep agalactiae how do we prevent strep agalactiae infection in neonate
Prophylactic Intrapartum penicillin administered to the mother
-
What are the hemolytic properties of strep viridans?
Alpha hemolytic
-
What gram staining does strep viridans have
Gram + coccus
-
Strep viridans capsule
Unencapsulated
-
What bacteria are found in the strep viridans group
- Strep mutans
- Strep sanguinis
-
What diseases do strep viridans cause
- Dental carries
- When passed into blood --> Subacute endocarditis and damaged heart valves
-
Which heart valve is most affected by bacteremic strep viridans infection
- Damaged heart valves ? Mitral valve
- Mitral valve prolapses very common + rheumatic fever affects mitral valve more
-
How do strep viridans affect heart valves?
- Previously damaged heart valve (mitral valve prolapse)
- Teeth cleaning --> strep viridans bacteria enter the blood stream --> transient bacteremia
- Strep viridans able to adhere any fibrin platelet aggregates at damaged tissue via dextrans
-
What are strep viridans virulence factors
Dextrans ? stick to platelets
-
How are dextrans formed
Formed by strep viridans from glucose
-
What does the name Enterococcus tell us?
- Entero = inhabits intestinal tract
- Coccus = cocci (not Enterobacter = rod)
-
What species are in the enterococcus genus
-
Which species is more common in the enterococcus genus
E. Faecalis
-
Which species is more serious in the enterococcus genus
E. Faecium
-
What medium are enterococci able to grow in
- 6.5% NaCl
- Bile resistant so can grow on bile
-
What infections do enterococci cause?
- UTI
- Endocarditis
- Biliary tree infections
-
E. Faecium resistance
- To almost all antibiotics
- Including vancomycin
-
What kind of infection is E. Faecium?
Nosocomial
-
What does VRE stand for
Vancomycin Resistant Enterococcus
-
How do you treat VRE?
- Linezolid ? expensive big gun antibiotic
- Tigecycline ? expensive bug gun antibiotic
-
What does the name staphylococcus aureus tell us?
- Staph = grape (Latin)
- Coccus = granule (Latin)
- Look like bunch of grapes under microscope
- Aureus = golden (Greek)
- When grows on blood agar, colonies have yellow or golden appearance to them
-
What gram staining is Staph Aureus
Gram + coccus (take up crystal violet in thick cell wall and hold on to it even after rinse and addition of red safranin)
-
How do you tell the difference between staph and strep?
Catalase test ? + in staphylococci
-
What does catalase do?
Convert hydrogen peroxide to water
-
How to tell the difference between staph aureus and other staph?
- Golden color when plated
- Coagulase test
- Beta hemolytic
- Grow on mannitol salt agar
-
What is coagulase
- An enzyme that converts fibrinogen --> fibrin
- Present in staph aureus
-
What does beta hemolysis look like on a petri dish?
Glowing halo of light on a red backdrop
-
What is special about mannitol salt agar
- salt selects only staph species
- see if it ferments mannitol ? positive (pink --> yellow) ? staph aureus
-
what is the main virulence factor for staph aureus?
Protein A
-
How does protein A work
- Protein A is a component of staph aureus cell wall
- Binds the Fc portion of immunoglobulins
- This prevents compliment from binding to the Fc region
- Prevents opsonisation and phagocytosis
- Allows it to better colonize its host
-
Where does staph aureus colonize
Nares
-
What types of diseases does staph aureus cause?
-
What infectious diseases does staph aureus cause?
- Pneumonia
- Skin infections
- Septic arthritis
- Endocarditis
- Osteomyelitis
-
What is typical of the pneumonia caused by staph aureus?
- See patchy infiltrates on X ray
- Usually a secondary post viral superinfection (after immune system has been weakened)
-
What is the most common cause of septic arthritis in adults?
Staph aureus
-
What kinds of skin infections does staph aureus cause?
- Cellulitis
- Impetigo
- Furuncles ? boils
- Carbuncles ? slightly larger boils
- Abscesses
-
What kind of endocarditis does staph aureus cause?
- Rapid onset (acute) bacterial endocarditis
- Usually in an IV drug user ? right sided infection on tricuspid valve
-
What is the most common cause of osteomyelitis in adults?
Staph aureus
-
What toxin mediated diseases does staph aureus cause?
- Scalded skin syndrome
- Toxic shock syndrome
- Food poisoning
-
What mediates scalded skin syndrome
Exfoliative toxin ? protease
-
What is the classic situation for someone getting toxic shock syndrome?
Someone leaving a foreign packing in for too long (gauze after rhinoplasty / tampon)
-
What kind of toxin is toxic shock syndrome toxin and how does it work
- Super antigen
- Causes nonspecific binding of MHC class 2 and T cell receptors --> over activation --> cytokine storm
- Could be fatal
-
What kind of food poisoning does staph aureus cause?
- Rapid onset due to preformed toxin (1-8 hours)
- Usually associated with vomiting more than diarrhea
- Associated with meats and mayonnaise etc.
-
What does MRSA stand for?
Methicillin Resistant Staph Aureus
-
How does MRSA become resistant?
Altering its Penicillin Binding Proteins
-
What does Penicillin Binding Protein do?
Helps build the cell walls
-
How do you treat MRSA?
Vancomycin
-
How do you treat staph aureus infection?
- Determine if it is methicillin sensitive
- If it is should use penicillin as it is more effective in killing bug
- Nafcillin = Naf for Staph
-
What gram staining is staph epidermidis
Gram + coccus ? takes up a lot of crystal violet stain
-
What does staph epidermidis often infect
- Implanted hardware
- Artificial joints
- Indwelling catheters
- Artificial heart valves (endocarditis)
-
Why is staph epidermidis called this way
Covers all of our skin
-
In what situation will staph epidermidis cause infections
When the skin is penetrated
-
How does staph epidermidis easily infect implants etc.?
Produces copious adherent biofilm which sticks to sleek metal and plastic surfaces
-
What is biofilm made of
Mesh of polysaccharides
-
What does biofilm do
- Helps bacteria stick to surfaces
- Acts as a coating that protects bacteria from antibiotics and immune cells
-
Why is staph epidermidis resistant to many antibiotics
The biofilm provides it with a protective coating
-
How do you treat staph epidermidis?
- Vancomycin for endocarditis
- Should replace any implants that are infected
-
Why is staph epidermidis often found in blood cultures
Part of the normal skin flora so easily contaminates cultures
-
How can you differentiate staph epidermidis from staph saprophyticus?
- Staph epidermidis is novobiacin sensitive
- Staph saprophyticus is novobiacin resistant
-
What gram staining is staph saprophyticus
Gram + coccus ? takes up a lot of crystal violet stain
-
What diseases does staph saprophyticus commonly cause
UTI ? in sexually active females
-
What features do staph epidermidis and staph saprophyticus have in common
- Catalase positive
- Urease positive
- Coagulase negative
-
how do you differentiate between staph aureus and staph saprophyticus or staph epidermidis?
- staph aureus ? coagulase positive
- staph epidermidis / saprophyticus ? coagulase negative
-
What does urease do
Converts urea into ammonia
-
What bacteria are urease positive
- Proteus
- Klebsiella
- Staph epidermidis
- Staph saprophyticus
-
what species are in the Neisseria genus
- Neisseria meningitidis
- Neisseria Gonorrhea
-
What gram staining are Neisseria
Gram ? diplococci
-
What biochemical properties do Neisseria have?
Oxidase +
-
How do you grow Neisseria?
- Chocolate agar
- VPN agar = Thayer martin agar
-
What do Neisseria species look like when grown on blood agar?
Unable to grow on blood agar
-
Why are Neisseria unable to grow on blood agar
Inhibited by some of the lipids and other elements in blood agar
-
What is chocolate agar
Heated blood agar
-
Why do we use chocolate agar to culture Neisseria?
Heating inactivates the inhibitors to growth found in blood agar
-
What is VPN agar
Agar enriched with vancomycin + polymyxins + nyastin
-
What is another name for VPN agar?
Thayer martin agar
-
Wo is more susceptible to Neisseria infections
Compliment deficiency of C5 ? C9
-
What does compliment deficiency of C5-C9 cause
Unable to form Membrane Attack Complex (MAC) --> increase susceptibility to Neisseria infections
-
What are the virulence factors of Neisseria?
-
What is the function of Neisseria pili?
- Attachment to mucosal surfaces
- Frequent genetic rearrangement --> antigenic variation
-
What does the antigenic variation of Neisseria mean for our immune system?
- Difficult to target
- Prevents any lasting immune response
-
How does Neisseria evade our immune system?
Antigenic variation of pili through frequent genetic rearrangements
-
What is IgA protease
Protein that cleaves IgA at its hinge point
-
What does IgA protease do?
- Cleaves IgA at its hinge point
- Facilitates survival along mucosal surfaces
-
How do Neisseria survive on mucosal surfaces?
IgA protease
-
What gram stain is Neisseria
Gram ? diplococci
-
What biochemical properties does Neisseria have?
Oxidase positive
-
How do you grow Neisseria?
- Chocolate agar
- VPN agar = Thayer martin agar
-
Who is susceptible to Neisseria infections?
C5-C9 compliment deficient patients due to inability to form MAC complex
-
What virulence factors does Neisseria meningitidis have
- IgA protease
- Pili that demonstrate antigenic variation
- Polysaccharide capsule
-
How is Neisseria meningitidis spread
Respiratory droplets
-
Where is Neisseria meningitidis spread
Close quarters ? e.g. dorms
-
What differentiates Neisseria meningitidis from Neisseria gonorrhea
- Ferments glucose and maltose (Meningitidis)
- Only ferments glucose (gonorrhea)
- Encapsulated (meningitidis)
- Non encapsulated (gonorrhea)
-
How does Neisseria meningitidis infection occur
Respiratory droplets --> colonize nasopharynx -->hematogenous spread
-
What is the Neisseria meningitidis capsule made of?
Polysaccharide
-
What is the function of the Neisseria meningitidis capsule?
Inhibits phagocytosis
-
What kind of vaccine is used for Neisseria meningitidis?
Contain polysaccharide capsule (types A, C, D)
-
Which polysaccharide capsules are included in the Neisseria meningitidis vaccine
-
Which strain of Neisseria meningitidis causes most infections in developed world and why
B because it is not included in the vaccine
-
Who is most susceptible to Neisseria meningitidis infections
- Sickle cell anemia
- Asplenic patients
-
Who more susceptible to infections caused by encapsulated organisms
- Sickle cell anemia
- Asplenic patients
-
Which organisms are asplenic patients more susceptible to
- Encapsulated organisms
- * Streptococcus pneumoniae
- * Haemophilus influenzae
- * Neisseria meningitidis
-
What happens when Neisseria meningitidis enters the blood stream
- Massive inflammatory response --> increased permeability of capillaries --> leakage of fluid into extravascular space --> hypovolemic shock --> peripheral vasoconstriction --> adrenal insufficiency --> farther exacerbation of shock
- Thrombocytopenia --> Characteristic petechial rash
-
What causes the massive inflammatory response to hematogenous Neisseria meningitidis?
Lipoolygosaccharides (LOS) outgrows surface of bacteria --> blebs off
-
What is LOS
LipoOligoSaccharide envelope protein of Neisseria meningitidis
-
What does petechial rash suggest in a patient?
Thrombocytopenia
-
What is DIC
Disseminated Intravascular Coagulation
-
What are the early signs of DIC?
Petechial rash --> purpura --> ecchymosis
-
What would you see in a physical exam of a patient with DIC?
- Oozing at the venipuncture sites
- Bleeding gums
-
What causes waterhouse frederichson syndrome
- Neisseria meningitidis
- Massive inflammatory response to LOS --> Hypovolemic shock --> peripheral vasoconstriction
-
What is waterhouse Frederichson syndrome
Adrenal infarction due to Neisseria meningitidis infection
-
What are the general stages of Neisseria meningitidis infection?
- Nasopharyngeal colonization
- Hematogenous spread (meningeal symptoms)
- Hypovolemic shock + DIC
- Waterhouse frederichson syndrome
-
How do you treat Neisseria meningitidis infection?
- 3rd generation cephalosporin that can penetrate the blood brain barrier
- Ceftriaxone
- Prophylactic treatment of close contacts with rifampin
-
Why do we give prophylaxis to close contacts in Neisseria meningitidis infection?
- Spread by respiratory droplets
- Highly contagious
-
What is defined as a ?Close contact? in Neisseria meningitidis infection
Someone who has spent over 8 hours with the patient during the 7 days prior to onset
-
What is the prophylaxis for Neisseria meningitidis infection?
Rifampin
-
What gram stain is Neisseria
Gram ? diplococci
-
What biochemical properties does Neisseria have?
Oxidase positive
-
How do you grow Neisseria?
- Chocolate agar
- VPN agar = Thayer martin agar
-
Who is susceptible to Neisseria infections?
C5-C9 compliment deficient patients due to inability to form MAC complex
-
What virulence factors do Neisseria have
- IgA protease
- Pili that demonstrate antigenic variation
-
What differentiates Neisseria meningitidis from Neisseria gonorrhea
- Ferments glucose and maltose (Meningitidis)
- Only ferments glucose (gonorrhea)
- Encapsulated (meningitidis)
- Non encapsulated (gonorrhea)
-
What kind of infection is gonorrhea?
STD ? Sexually Transmitted Disease
-
where can Neisseria gonorrhea grow
facultative intracellular
-
what cells does Neisseria gonorrhea invade?
polymorphonuclear lymphocytes (PMN)
-
what is the area that Neisseria gonorrhea most commonly affects?
genetelia of men and women
-
what can Neisseria gonorrhea cause in men
- urethritis --> prostatitis --> orchitis
- polyarthritis
-
what can Neisseria gonorrhea cause in women
- urethritis --> pelvic inflammatory disease (PID) --> spread into peritoneum
- polyarthritis
-
what is PID
Pelvic inflammatory disease
-
What can PID cause
Scarring --> infertility / atopic pregnancies
-
What does Neisseria gonorrhea urethritis look like?
Thick white purulent discharge
-
What does chlamydia trachomatis urethritis look like?
Thin watery purulent discharge
-
What are the main causes of urethritis?
- Chlamydia trachomatis
- Neisseria gonorrhea
-
What is Fitz Hugh Curtis syndrome?
Neisseria gonorrhea infection spreading into peritoneum
-
What can Fitz Hugh Curtis syndrome cause
Violin string adhesions ? adhesions to the capsule of the liver (long + thin)
-
Where does Neisseria gonorrhea polyarthritis occur
Knee ? often asymmetric
-
Who does Neisseria gonorrhea affect
Young sexually active people
-
How do you diagnose Neisseria gonorrhea polyarthritis?
Joint tap with purulent synovial fluid that doesn?t gram stain
-
Why is gram stain ineffective in diagnosis of Neisseria gonorrhea?
Intracellular
-
How do we get congenital Neisseria gonorrhea infection?
Expecting mother with untreated gonococcal infection passes it to child during delivery
-
How will congenital Neisseria gonorrhea infection manifest
Purulent conjunctivitis that occurs within first 5 days of life
-
How will congenital chlamydia trachomatis infection manifest
Purulent conjunctivitis that occurs a week after birth
-
What are the main differences between Neisseria gonorrhea and chlamydia trachomatis infections?
- Urethral discharge is thick and very purulent (gonorrhea)
- Urethral discharge is thin and watery (chlamydia)
- Neonatal conjunctivitis occurs within first 5 days of life (gonorrhea)
- Neonatal conjunctivitis occurs after 1 week of life (chlamydia)
-
How do we treat Neisseria gonorrhea infection?
- Ceftriaxone (gonorrhea)
- Macrolides ? azithromycin / doxycycline (chlamydia co infection)
-
Why do we treat patients with more than one antibiotic?
Chances of co infection with chlamydia trachomatis are very high so we should treat both in case
-
What gram stain is Brucella
Gram ? coccobacillus
-
Where can we find Brucella
Zoonotic ? associated with cattle and other farming animals
-
What is the reservoir for Brucella?
Farm animals ? cows / sheep / goats / pigs
-
What species are there in Brucella genus?
- Different species for different animals
- Cow ? Brucella bordis
-
Who is affected by Brucella infections
- Direct contact with animals ? people with direct contact with animals
- * Veterinarian
- * Slaughter house workers
- * Rancher
-
How is Brucella transmitted
- Direct contact with animals
- Indirect contact by consumption of milk / chees products
-
Where can Brucella grow
- Facultative intracellular
- Inside cells such as macrophages
-
How do Brucella survive intracellularly in macrophages?
Prevent phagolysosome fusion
-
What does Brucella cause
Brucellosis
-
What is the clinical presentation of brucellosis?
- Primary symptoms ? non specific
- * Undulant fever
- * chills
- * anorexia
- enlargement of reticuloendothelial organs (spleen / liver / lymph nodes)
- osteomyelitis
-
what is undulant fever
- pattern of fever that rises and falls
- can be caused by brucellosis
-
where can Brucella spread in the body and why
able to survive in macrophages and be carried to multiple organs in reticulo endothelial system
-
what is the pathogenesis of brucellosis?
- Brucella is taken up by macrophages
- Prevents phagolysosome fusion
- Replicates intracellularly until host cell lyses
- Spread systemically
-
Which organs are part of the reticulo endothelial system
-
What is a complication of chronic brucellosis?
Osteomyelitis
-
How do we treat brucellosis?
Tetracycline (doxycycline) AND rifampin
-
What gram stain is Francisella tularensis
Gram ? coccobacillus
-
What does Francisella tularensis cause
Tularemia
-
Where can we find Francisella tularensis
Zoonotic ? rabbits
-
What is the main reservoir for Francisella tularensis?
Rabbits
-
How is Francisella tularensis transmitted
- Direct contact with rabbits ? handling rabbits / eating rabbit meat
- Indirect contact ? tick vector
- Aerosolized
-
Which tick transmits Lyme disease caused by Borrelia burgdorferi
Ixodes tick
-
Which tick transmits Francisella tularensis
Dermacentor tick
-
Why is Francisella tularensis possible to use in bioterrorism
Can be aerosolized
-
What shape is Francisella tularensis
Coccobacillus
-
Where can Francisella tularensis grow
Facultative intracellular
-
Which kind of immunity is important for recovery from Francisella tularensis infection
Cell mediated immunity (intracellular organism)
-
What is the pathogenesis of Francisella tularensis infection?
- Tick bites human
- Bacteria enters at site of bite --> painful ulcer
- Enters macrophages
- Travels through lymph system --> reticuloendothelial organs
-
What is the clinical presentation of tularensis?
- Painful ulcer at tick bite site
- Granulomas with caseating necrosis in reticuloendothelial organs (lymph nodes)
- Regional lymphadenopathy
- How do we treat Francisella tularensis infection?
- Aminoglycosides ? streptomycin
-
What does Bordetella pertussis infection cause?
Whooping cough
-
What gram stain is Bordetella pertussis
Gram ? coccobacillus
-
How is Bordetella pertussis transmitted?
Respiratory droplets
-
How does Bordetella pertussis cause infection?
- Attaches to respiratory epithelium using pili
- Releases toxins to cause systemic effects
-
What are virulence factors of Bordetella pertussis?
- Pilli ? filamentous hemagglutinin
- Toxins
- * Pertussis toxin
- * Adenylate cyclase toxin
- * Tracheal toxin
-
What does Bordetella pertussis use filamentous hemagglutinin for?
Attaching to respiratory epithelium
-
What is the name of Bordetella pertussis pili?
Filamentous hemagglutinin
-
How does Bordetella pertussis cause systemic effects?
Releasing toxins after attaching to respiratory epithelium
-
What do antibodies target in Bordetella pertussis?
Filamentous hemagglutinin pili
-
Which toxins does Bordetella pertussis have
- Pertussis toxin
- Adenylate cyclase toxin
- Tracheal toxin
-
How does Bordetella pertussis work?
- ADP ribosylation of Gi (inhibitory G) protein --> Gi is inhibition --> rise in cAMP
- Also disables chemokine receptors for lymphocytes --> Lymphocytes unable to enter lymphoid tissue --> stuck in blood stream --> massive lymphocytosis
-
What is the function of Gi protein?
- Inhibitory G protein
- Inhibits cAMP formation
-
What causes massive lymphocytosis in Bordetella pertussis
Pertussis toxin disables chemokine receptors for lymphocytes
-
How does
Acts as an adenylate cyclase --> Increases cAMP levels
-
What do Bordetella pertussis and Bacillus anthracis have in common?
- Adenylate cyclase toxin (Bordetella pertussis)
- Edema factor (Bacillus anthracis)
-
How does tracheal toxin work?
- Damages ciliated cells in respiratory epithelium
- Cleaves cilia
-
Where do we find tracheal toxin?
Part of peptidoglycan wall of Bordetella pertussis
-
What is the target for tracheal toxin?
Ciliated cells in respiratory epithelium
-
Who is most affected by Bordetella pertussis infection
Children
-
What is the clinical presentation of Bordetella pertussis infection?
- Catarrhal phase ? Initially nonspecific symptoms (1-2 weeks)
- Paroxysmal phase ? whooping cough (2 weeks ? 2 months)
- Convalescent phase ? gradual reduction in symptoms (up to 3 months)
-
How long does the catarrhal phase of Bordetella pertussis infection last?
1-2 weeks
-
What is the clinical presentation of the catarrhal phase of Bordetella pertussis infection?
- Nonspecific symptoms
- * Conjunctival injection
- * Lacrimation
- Lasts 1-2 weeks
-
How long does the paroxysmal phase of Bordetella pertussis infection last?
2 weeks ? 2 months
-
What is the clinical presentation of the paroxysmal phase of Bordetella pertussis infection?
Intense bouts of coughing that get children so out of breath that when eventually breath in it makes characteristic whooping sound on inspiration
-
How long does the convalescent phase of Bordetella pertussis infection last?
Up to 3 months
-
What is the clinical presentation of convalescent phase of Bordetella pertussis infection?
Gradual reduction in symptoms
-
What is another way to call whooping cough and why?
- 100-day cough
- Lasts for a very long time with phases going on for months
-
How do we treat Bordetella pertussis infection?
- Macrolides ? remove bacteria in the respiratory tract
- Vaccination
-
Why is it important to start treatment early in Bordetella pertussis infection?
- Macrolides can remove the bacteria but do not affect the toxins already circulating in the body
- So macrolides are ineffective in symptom improvement
-
What kind of vaccines do we have for Bordetella pertussis?
- Killed vaccine ? no longer in use
- Acellular vaccine
-
What is the acellular vaccine for Bordetella pertussis made of?
Purified antigens
-
What is DPT
- Vaccine given to children
- Diphtheria toxoid
- Pertussis antigens
- Tetanus toxoid
-
What gram stain is Haemophilus influenzae
Gram ? coccobacillus
-
What shape does Haemophilus influenzae have
Coccobacillus
-
How do we grow Haemophilus influenzae?
Chocolate agar with Factor 5 (NAD) and Factor 10 (hematin)
-
-
What is factor 10
Hematin (hema-ten)
-
Which bacteria required factor 5 + 10 to grow
Haemophilus influenzae
-
How is Haemophilus influenzae transmitted
Aerosol transmission
-
What does Haemophilus influenzae infection cause
- Pneumonia
- Epiglottitis
- Otitis media
- Meningitis
- Sepsis
- Septic arthritis
-
What is a common causes epiglottitis?
Haemophilus influenzae
-
What is the clinical presentation of epiglottis caused by Haemophilus influenzae?
- Inflamed epiglottis ? cherry red epiglottis
- Inspiratory stridor
- Drooling
-
Who is most affected by epiglottitis caused by Haemophilus influenzae
Children
-
What is otitis media
Inflammation of the middle ear
-
Which form of Haemophilus influenzae causes meningitis
Type B capsular strain
-
Who is most affected by septic Haemophilus influenzae infections
- Asplenic patients
- Sickle cell patients
-
What is the function of the spleen in relation to bacteria?
Remove encapsulated organisms
-
Why is Haemophilus influenzae meningitis rare in the USA
Successful vaccination efforts
-
What kind of vaccine is vaccine for Haemophilus influenzae?
Polysaccharide capsular antigen (type B) conjugated to the diphtheria toxoid
-
Why do we have conjugated vaccines?
- Proteins increase antigenicity of capsular polysaccharide
- Body produces strong IgG response
-
When do we vaccinate for Haemophilus influenzae?
2-18 months
-
How do you treat Haemophilus influenzae?
- Beta lactams
- Meningitis / systemic disease ? ceftriaxone
- Prophylaxis for meningitis ? rifampin
-
How do we treat Haemophilus influenzae meningitis?
Ceftriaxone
-
what do you use for prophylaxis of Haemophilus influenzae in close contacts?
rifampin
-
What gram stain is Listeria monocytogenes
Gram + bacillus
-
What is Listeria monocytogenes most associated with?
Infections in pregnant women
-
What are listerias hemolytic properties
Beta hemolytic with narrow zone of hemolysis
-
Where can Listeria grow
Facultative intracellular organism
-
What does listeria use its flagella for?
Tumbling motility when it is extracellular
-
How does listeria move intracellularly?
- Actin rockets ? rapidly polymerizes actin against the bacteria wall so that it is propelled along in opposite direction
- Can be from cell to cell
-
How does listeria move from cell to cell?
Through actin rocket propulsion across cell membranes
-
What biochemical markers does listeria have?
Catalase + (like staph)
-
Why are listeria able to contaminate food items
Able to survive and multiply in near freezing temperatures ? contaminates refrigerated items
-
What kind of food does listeria contaminate?
- Unpasteurized milk
- Packages meat
- Soft cheeses
-
Who does listeriosis affect most
Pregnant women ? 20x more likely
-
What does listeriosis during pregnancy cause
- Early in pregnancy ? termination
- Later in pregnancy ? diseases in the newborn
-
How do we decrease likelihood of getting listeriosis in pregnant women?
Discouraged from eating unpasteurized products and soft cheeses
-
What diseases does listeria monocytogenes cause?
Meningitis in newborns and adults over 60
-
What are the 3 most common causes of meningitis in newborns
- Group B strep
- E. coli
- Listeria Monocytogenes
-
What is the standard empirical treatment for meningitis in adults?
- Vancomycin (gram +)
- AND Ceftriaxone (gram -)
- What is the treatment for meningitis in adults over 60?
- Vancomycin (gram +)
- AND Ceftriaxone (gram -)
- And Ampicillin (listeria)
-
How do we treat listeriosis?
Ampicillin
-
What are the gram staining properties of Corynebacterium?
Gram + rod (club shaped)
-
What does Corynebacterium diphtheriae cause
Diphtheria
-
What does Corynebacterium diphtheria look like?
- Club shaped ? Y or V formation
- Contains metachromatic granules
-
How do you stain metachromatic granules?
Aniline dyes
-
What toxin does Corynebacterium diphtheria produce?
Diphtheria Exotoxin
-
What is the structure of Corynebacterium diphtheria exotoxin?
- 2 subunits A and B
- A ? Active
- B ? Binding
-
What does Corynebacterium diphtheria exotoxin do?
Causes ADP ribosylation of elongation factor 2 --> inhibits ribosome function --> inhibits protein synthesis cell death
-
What is a pseudomembrane of the oropharynx
Thick greyish exudate over the mucosal surface
-
What bacteria causes a pseudomembrane in the oropharynx
Corynebacterium diphtheriae
-
What bacteria cause pseudomembrane formation
- Corynebacterium diphtheriae
- Clostridium difficile
-
Where are Corynebacterium diphtheriae psuedomembranes formed
Throat and tonsils (oropharynx) --> larynx --> trachea
-
How is Corynebacterium diphtheriae infection transmitted
Respiratory droplets
-
What symptoms does Corynebacterium diphtheriae cause?
- Airway obstruction (when spread to larynx and trachea)
- Bulls neck ? severe lymphadenopathy with characteristic thickening of the neck
-
What causes bulls neck
Corynebacterium diphtheriae lymphadenopathy --> thickening of the neck
-
When causes systemic effects of Corynebacterium diphtheriae infection
Exotoxin going into bloodstream
-
What systemic effects can Corynebacterium diphtheriae infection cause
- Cardiotoxic effects
- * Life threatening myocarditis
- * Arrhythmias
- * Heart block
- Neurotoxic effects
- * Local paralysis that begin in the posterior pharynx --> other cranial nerve deficits
-
What life threatening effects does Corynebacterium diphtheriae have
Life threatening myocarditis
-
How does diphtheria exotoxin cause neurogenic effects?
Damages myelin of nerve fibers
-
How do you definitively diagnose Corynebacterium diphtheriae infection?
- Good clinical history + physical exam ? gives a good idea but not definitive
- Culturing
- Toxin assay
-
how do you grow Corynebacterium diphtheriae?
- Tellurite media
- Loeffler?s media
-
How do you differentiate between toxic and nontoxic strains of Corynebacterium diphtheriae?
ELEKs test
-
How does ELEKs test work
- In vitro assay on filter paper that has antitoxin on it
- If toxin binds on it there is a reaction --> strain is toxic
-
What is ELEKs test used for
Differentiating between toxic and nontoxic strains of Corynebacterium diphtheriae
-
Which population is at greater risk of getting diphtheria
Unvaccinated (immigrant) children
-
What kind of vaccine is Corynebacterium diphtheriae vaccine?
Toxoid vaccine
-
What is a toxoid vaccine?
Consists of inactivated exotoxin bound to protein
-
What kind of immune response do we get from toxoid vaccines
Powerful IgG response
-
What is DPT vaccine
- Diphtheria ? toxoid vaccine (Corynebacterium diphtheriae)
- Pertussis ? acellular vaccine (Bordetella pertussis)
- Tetanus ? toxoid vaccine (Clostridium tetani)
-
How do you treat diphtheria?
- Preventative vaccination
- Passive immunization
-
What is passive immunization
Administering antitoxoid
-
What gram stain is Escherichia coli
Gram ? rod (enterobactericiae)
-
What bacteria are part of the Escherichia coli group
- EHEC ? Entero Hemorrhagic
- ETEC ? Entero Toxigenic
- EPEC ? Entero Pathogenic
- EIEC ? Entero Invasive
-
What biochemical properties do Escherichia coli have?
- Ferment lactose
- Catalase +
-
How do you test for lactose fermentation?
Grow pink on MacConkey agar
-
Which bacteria are lactose fermenters
- Klebsiella
- Enterobacter
- Serratia
- Escherichia coli
-
What are Escherichia coli virulence factors?
- Capsule
- Fimbriae
- LipoPolySaccharide (LPS) endotoxin
-
What is Escherichia coli capsule made of?
K antigen
-
What do we use to serotype Escherichia coli?
K antigen of the capsule
-
What is EMB agar
Eosin Methylene blue agar
-
how does Escherichia coli look on EMB agar?
metallic green sheen
-
what is necessary for Escherichia to cause urinary tract infection
fimbriae
-
what does Escherichia coli infection cause?
- urinary tract infection (UTI)
- sepsis
- meningitis in neonates
-
what is the number one cause of urinary tract infection?
Escherichia coli
-
What is the number one cause of gram ? sepsis
Escherichia coli
-
What is the virulence factor important for causing Escherichia coli sepsis?
Lipopolysaccharide (LPS) endotoxin
-
What does Escherichia coli endotoxin cause?
Sepsis
-
Where is Escherichia coli endotoxin located
Outer cell membrane
- What is a common virulence factor for all gram ? bacteria
- Lipopolysaccharide (LPS) endotoxin
-
What virulence factor must be present for Escherichia coli to cause meningitis in neonates
K capsular antigen
-
How is Enterohemorrhagic Escherichia coli most commonly transmitted
Undercooked meat (e.g. hamburgers)
-
What does Enterohemorrhagic Escherichia coli infection cause
- Bloody diarrhea
- Hemolytic uremic syndrome (HUS)
-
How can you differentiate Enterohemorrhagic Escherichia coli from other E. coli?
Does not ferment sorbitol
-
What are Enterohemorrhagic Escherichia coli virulence factors
- Capsule
- LPS endotoxin
- Fimbriae
- Shiga like toxin
-
What toxin does Enterohemorrhagic Escherichia coli secrete
Shiga like toxin
-
How does shiga like toxin cause damage
Inhibits ribosomes at the 60S position
-
What can shiga like toxin cause
- Tissue damage
- Hemolytic Uremic Syndrome (HUS) in children under 10
-
What is the pathogenesis of hemolytic uremic syndrome?
- Shiga (like) toxin damages endothelial cells of the capillaries in the glomerulus
- Damaged endothelial lining becomes thrombogenic --> platelets adhere
- Clumps of platelets lyse red blood cells as they pass through capillaries
-
Which Enterohemorrhagic Escherichia coli serotype causes massive outbreaks
O157 H7
-
What is O157 H7
Enterohemorrhagic Escherichia coli strain known to cause massive outbreaks
-
What does Enterotoxigenic Escherichia coli infection cause
Travelers diarrhea
-
How is Enterotoxigenic Escherichia coli transmitted
Water sources
-
Where is Enterotoxigenic Escherichia coli commonly found
Mexico in the water
-
What virulence factors does Enterotoxigenic Escherichia coli have
- Capsule
- Fimbriae
- LPS endotoxin
- Heat labile toxin
- Heat stable toxin
-
Which toxins does Enterotoxigenic Escherichia coli secrete
- Heat labile toxin
- Heat stable toxin
-
How does Enterotoxigenic Escherichia coli heat labile toxin work
Increases cAMP
-
How does Enterotoxigenic Escherichia coli heat stable toxin work
Increase cGMP
-
Which Enterotoxigenic Escherichia coli and Vibrio cholerae toxins are similar
- Heat labile toxin (Enterotoxigenic Escherichia coli)
- Cholera toxin (Vibrio cholerae)
- Both increase cAMP
-
What is the clinical presentation of Enterotoxigenic Escherichia coli infection?
Watery diarrhea
-
What gram stain is salmonella
Gram ? rod (Enterobacteriaceae)
-
What virulence factors does salmonella have
- Motile
- Encapsulated
- Facultative intracellular (macrophages)
-
What is a common feature of all motile Enterobacteriaceae?
H2S +
-
How do we test for H2S positivity?
Black colonies on Hektoen enteric agar
-
What biochemical properties do salmonella have?
-
Why are do you need a high dose of salmonella to cause infection
Acid labile ? easily degraded in the stomach
-
Which Enterobacteriaceae requires high doses to cause infection
Salmonella (1,000 organisms to cause infection)
-
Which Enterobacteriaceae requires very low dose to cause infection
Shigella (10-100 organisms to cause infection)
-
Who is more susceptible to salmonella infection
- Patients with lowered stomach acidity
- * Omeprazole (treatment for reflux)
- * Pernicious anemia
-
How do salmonella infections progress?
Ingested --> stomach --> small intestine --> colon --> lymphatics --> taken up by macrophages --> blood
-
What is the reservoir for salmonella typhi?
- Gallbladders of chronic carriers
- What does salmonella typhi infection cause
- Enteric fever ? typhoid fever
- Osteomyelitis in patients with sickle cell disease
-
What is the clinical presentation of enteric fever?
- Rose colored macules on abdomen (25% of patients)
- Usually constipation
- Can be diarrhea ? pea soup colored
-
What is the number one cause of osteomyelitis in patients with sickle cell disease?
Salmonella typhi
-
How do we treat salmonella typhi infection?
- Fluoroquinolones
- Vaccination
-
What kind of vaccine do we have for salmonella typhi?
Live attenuated
-
What bacteria can cause paratyphoid fever
- Salmonella enterica?subsp.?Enterica
- * Salmonella enteritidis
- * Salmonella Typhimurium
- * Salmonella infantis
- * Salmonella Hadar
- * Salmonella Heidelberg
- * Salmonella paratyphi
- * Salmonella Typhi
-
how do we get salmonella enteritidis infection?
uncooked chicken
-
what is the main reservoir of salmonella enteritidis?
chickens
-
what does salmonella enteritidis cause
inflammatory diarrhea
-
what is type 3 secretion system
protein that detects eukaryotic cells and secretes protein that helps with infectivity
-
which bacteria have type 3 secretion system
- salmonella enteritidis
- shigella
- Yersinia pestis
-
What virulence factors does salmonella enteritidis have
- Capsule
- Motile
- Facultative intracellular (macrophages)
- Type 3 secretion system
-
What gram stain is shigella
Gram ? rod (Enterobacteriaceae)
-
What do shigella infections cause
Gastroenteritis with blood diarrhea
-
What is the clinical presentation of shigella gastroenteritis?
Bloody diarrhea
-
What species are in the shigella genus
- Shigella sonnei
- Shigella dysenteriae
-
How does shigella look when cultured on hektoin agar?
Green colonies
-
How do you differentiate shigella from salmonella?
- Green colonies on hektoin agar (shigella)
- Black colonies on hektoin agar (salmonella)
- Immotile (shigella)
- Motile (salmonella)
- Acid stabile (shigella)
- Acid labile (salmonella)
-
Which Enterobacteriaceae requires very low dose to cause infection
Shigella (10-100 organisms to cause infection)
-
Why are only small doses of shigella needed to cause infection
Acid stabile
-
How do shigella infections progress
Ingested --> intestinal lumen --> M cells --> lymphoid tissue + enterocytes
-
What cells are found in peyers patches
M cells
-
What is the function of M cells?
Sample things in the lumen and bring back antigens to the immune cells on other side of intestinal lumen
-
How does shigella get out of the intestinal lumen?
- Induces M cells to phagocytose them
- Escape from phagolysosome before they get degraded
- Use M cell?s actin to make a tail that it uses to propel itself from one cell to another
-
How does shigella move from one cell to another?
Use host cells actin cytoskeleton to create a tail that it can use to propel itself from one cell to another
-
What is a similarity between shigella and listeria?
- Actin rockets (listeria)
- Use actin tails created from M cell actin to propel itself (shigella)
-
What are virulence factors of shigella?
- Facultative intracellular
- Shiga toxin (salmonella dysinteriae)
- Type 3 secretion system
-
Which enterobactericiae are facultative intracellular
-
What does shigella do once it has invaded lymphoid tissue + enterocytes surrounding M cells
Damages tissues + releases cytokines --> large immune response
-
What triggers the large immune response in shigella infection?
Release of cytokines
-
What does the large immune response in shigella infections cause?
- Inflammatory diarrhea
- Fecal blood and leukocytes
-
What can shigella dysinteriae cause
- Gastroenteritis with blood diarrhea
- Hemolytic Uremic Syndrome (HUS)
-
What is hemolytic uremic syndrome
- Hemolytic uremic syndrome
- Presents as acute renal failure
-
What causes hemolytic uremic syndrome
- E.coli (more common)
- Shigella dysinteriae
-
What causes Hemolytic uremic syndrome
Shiga toxin
-
How does shiga toxin cause hemolytic uremic syndrome
- Once in the blood stream it can induce endothelial damage including in the endothelium of the kidney --> activates platelets --> aggregation of platelets --> drop in platelet count
- Platelet clots lyse red blood cells as they pass by
-
What is a schistocytes
Helmet shaped red blood cell caused by hemolysis as red blood cells pass through platelet aggregates
-
Who is affected by hemolytic uremic syndrome
Patients under 10 years of age (shigella)
-
How does shiga toxin cause tissue damage
Binds to 60S subunit of ribosomes --> inhibits translation
-
What does shigella use type 3 secretion system for
Secrete inflammatory cytokines
-
What species are in the yersiniae genus
- Yersinia enterocolitica
- Yersinia pestis
-
Who discovered Yersinia pestis
Alexander yersin ? Swiss French
-
What is the cause of the black plague?
Yersinia pestis
-
What gram stain are yersiniae
- Gram ? rod (enterobactericiae)
- Bipolar staining
-
How is Yersinia enterocolitica transmitted
- Primarily through dog feces
- Contaminated milk products
-
Who is commonly affected by Yersinia enterocolitica
Children
-
Which bacteria contaminate milk
- Listeria
- Yersinia enterocolitica
-
Why are Yersinia enterocolitica and listeria able to infect milk
Resistant to cold temperatures
-
What is bipolar staining
- Stains more heavily on ends and lighter in middle
- Looks like a safety pin
-
Which bacteria has bipolar staining
- Yersinia enterocolitica
- Pasteurella multocida
-
What virulence factors does Yersinia have
Capsule
-
What does Yersinia enterocolitica infection cause
- Diarrhea
- Invasive --> bloody diarrhea + systemic effects
-
What is the clinical presentation of systemic Yersinia enterocolitica?
- Fever
- leukocytosis
- abscesses
- intestinal perforation
- intussusception
- paralytic ilius
- many other GI tract effects
- can mimic appendicitis
-
what kind of pain can Yersinia enterocolitica cause when in abdomen?
- mimic appendicitis
- right lower quadrant pain
-
what causes the black death / bubonic plague?
Yersinia pestis
-
what does Yersinia pestis infection cause
bubonic plague / black death
-
when did the black death pandemic occur
14th century
-
What is the main reservoir of Yersinia pestis?
- Rodents (e.g. rats)
- Prairie dogs
-
How is Yersinia pestis transmitted
Fleas bite the rodents and then bite the human
-
What is the clinical presentation of bubonic plague?
- Buboes ? swollen tender lymph nodes
- Abscesses in organs
- DIC
- Cutaneous hemorrhage
-
How does Yersinia pestis infection progress
Once infection established bacteria rise to higher and higher concentrations --> blood stream
-
What causes disseminated intracellular coagulation in Yersinia pestis infection
LPS endotoxin
-
What is the clinical presentation of disseminated intracellular coagulation due to Yersinia pestis?
- Necrosis of digits and other appendages
- (blackening of fingers)
-
What virulence factors does Yersinia pestis have
- LPS endotoxin
- Exotoxins
- Yersinia associated Outer Proteins (YOPs)
- Type 3 secretion system
-
What is the function Yersinia associated outer proteins
- Macrophage and neutrophil dysfunction by inhibiting phagocytosis and cytokine production
- Allows Yersinia to replicate rapidly and spread
-
What is the function of type 3 secretion system in Yersinia pestis?
Secrete Yersinia associated outer proteins
-
How do you treat Yersinia pestis infection?
- Aminoglycosides (streptomycin) + tetracycline
- Vaccine
-
What kind of vaccine is Yersinia pestis vaccine?
Killed vaccine
-
What species are in the vibrio genus
- Vibrio cholera
- Vibrio parahaemolyticus
- Vibrio vulnificus
-
Where is cholera endemic
Developing countries
-
What is the gram stain of vibrio?
- Gram ? curved rod (enterobactericiae)
- Coma shaped
-
What shape are vibrio
Coma shaped
-
What does vibrio cholera infection cause?
Cholera ? perfuse watery diarrhea (10-20L a day)
-
What is the clinical presentation of cholera?
- Perfuse (10-20L/day) watery diarrhea
- Rice water stool
-
How is vibrio cholerae transmitted
Fecal oral root by poor sanitation --> contamination of food and water sources by human feces
-
What is the pathogenesis of cholera?
Cholera toxin secreted by vibrio cholerae
-
What are the virulence factors of vibrio cholerae?
-
What is the function of fimbriae in vibrio cholerae infection?
Attach the ganglioside receptors in intestinal wall
-
How does cholera toxin work?
- Binds to and constitutively activates adenylate cyclase of the GS pathway
- Increases cAMP
- Secretion of water into intestinal lumen
-
How do we treat vibrio cholerae infection?
- Oral rehydration therapy with electrolytes
- Antibiotics ? reduce duration of symptoms
-
How do we grow vibrio cholerae?
Alkaline media
-
Why is it difficult for vibrio cholerae to survive in the stomach?
Acid labile
-
What biochemical properties does vibrio cholerae have?
-
Where can we find vibrio parahemolyticus and vibrio vulnificus
Contaminate sea food
-
What gram stain is campylobacter
- Gram ? curved rod (enterobactericiae)
- Coma shaped
-
What does campylobacter jejuni cause
Enterocolitis and diarrhea
-
How do we culture campylobacter?
Thermophilic ? likes warmth (42oC)
-
What is the main reservoir of campylobacter jejuni?
Intestinal tract of other animals (e.g. poultry)
-
How is campylobacter jejuni transmitted
- Fecal oral transmission
- During slaughtering process gut is perforated and intestinal contents can leak out and infect the meat
-
What does campylobacter jejuni infection causes
- A lot of watery diarrhea
- Invasive ? bloody diarrhea + bacteremia
- Reiter?s syndrome ? reactive arthritis
-
What shape is campylobacter jejuni
Coma shaped
-
What biochemical properties does campylobacter jejuni have?
Oxidase positive
-
Which bacteria are curved gram ? rods
- Campylobacter jejuni
- Helicobacter
- Vibrio
-
What is a common feature for all curved gram ? rods
Oxidase positive
-
How does campylobacter jejuni disease progress
Enters gut --> penetrates mucosa --> enters the blood stream
-
What is Reiter?s syndrome
- Reactive arthritis
- Seronegative spondyloarthropathies that can be precipitated by campylobacter jejuni infection
-
What can cause Reiter?s syndrome
Campylobacter jejuni infection
-
What is the most classic causes guillain-barr? syndrome?
Complications of Campylobacter jejuni infection
-
How does guillain-barr? syndrome occur
Body has autoimmune response that causes demyelination of peripheral nerves
-
What is the clinical presentation of guillain-barr? syndrome?
Ascending paralysis
-
What is the clinical presentation of botulism?
Descending paralysis
-
What is the difference between guillain-barr? syndrome and botulism?
- Ascending paralysis (guillain-barr? syndrome)
- Descending paralysis (botulism)
-
What does the name helicobacter pylori tell us?
- Helicon ? helical shape
- Pylori ? infects pylorus in the antrum of our stomach
-
What gram stain is helicobacter pylori
Gram ? curved rod (enterobactericiae)
-
What shape does helicobacter pylori have
Helical shape
-
Who is affected by helicobacter pylori
- 80% adults in developing countries
- 50% adults in USA
-
What virulence factors does helicobacter pylori have
Flagella ? motile
-
What does helicobacter pylori use its flagella for
Spins and whips flagella around to propel it around the stomach
-
What kind of motility does helicobacter pylori have?
Spinning
-
What biochemical properties does helicobacter pylori have?
-
What is the function of urease?
- Splits urea into ammonia and CO2
- helps reduce the acidity of the environment
-
why does helicobacter pylori need to invade the stomach and why
urease ? to negate the acidity of the stomach
-
how do we screen for helicobacter pylori infection?
- urea breath test
- biopsy during endoscopy
-
how do we perform the urea breath test?
- patient swallow urea labelled with radioactive carbon
- this is split into CO2 and ammonia
- CO2 labelled with radioactive carbon is exhaled
- Detect radioisotopes on exhalation
-
What do we detect in urea breath test?
CO2 labelled with radioisotopes
-
How do we detect helicobacter pylori using biopsy?
Directly check for urease with rapid test
-
What does helicobacter pylori infection cause
Ulcers
-
What is the most common cause of duodenal ulcers?
Helicobacter pylori
-
How does helicobacter pylori cause ulcers
Chronic infections --> reducing somatostatin / increasing gastrin production --> increased acid production
-
What is the risk associated with untreated duodenal ulcers?
- Adenocarcinoma of the stomach
- Lymphoma of the mucous associated lymphoid tissue (MALToma)
-
What bacteria is linked to almost half of gastric carcinomas
Helicobacter pylori
-
What is a possible treatment for MALToma?
Treatment of helicobacter pylori
-
How do we treat helicobacter pylori infection?
- At least triple therapy
- Proton pump inhibiter (PPI)
- Amoxicillin
- Macrolide ? clarithromycin
-
Why do we use a proton pump inhibiter in treatment of helicobacter pylori infections?
Counter increased acid production caused by chronic helicobacter pylori infections
-
What gram stain are pseudomonas
Gram ? rod (enterobactericiae)
-
Where do we find pseudomonas?
Aquatic environments
-
Why do pseudomonas cause hot tub folliculitis
Thrive in aquatic environments
-
What biochemical properties do pseudomonas have?
-
What organisms are chronic granulomatous disease patients at high risk for
Catalase + organisms
-
Which patients are most susceptible to catalase positive organisms
Patients with Chronic Granulomatous Disease
-
Which bacteria are patients with CGD most susceptible to
- Chronic Granulomatous Disease ? catalase + organisms
- * SPACE, nous voyons notre chat, gros petit tresor, houra!
- * Staphylococci
- * Pseudomonas aeruginosa
- * Aspergillus fumigatus
- * Candida
- * Enterobacteriaceae
- * Neisseria
- * Vibrio
- * Nocardiae
- * Campylobacter
- * Helicobacter
- * Gardnerella vaginalis
- * Pseudomonas cepacia
- * Mycobacterium Tuberculosis
-
What does pseudomonas look like when plated
- Blue green pigment
- Fruity grape like odor
-
What produces the blue green pigment in pseudomonas?
-
Which bacteria can cause wounds to turn blue
- Pseudomonas
- Blue green pigments ? pyocyanin + pyoverdin
-
How do you grow pseudomonas?
- Obligate aerobe
- Thrives in aquatic environments
-
How do you distinguish pseudomonas from the rest of the Enterobacteriaceae family?
- Obligate aerobe (pseudomonas)
- Facultative anaerobe (others)
-
What can pseudomonas infection cause
- Gram ? nosocomial pneumonia
- Pulmonary infection in cystic fibrosis patients
- Osteomyelitis
- Infection of burn wounds
- Urinary Tract Infection (UTI)
- Skin lesions
- Otitis externa
-
What is the number one cause of gram ? nosocomial pneumonia
Pseudomonas
-
Who is most affected by pulmonary infections of pseudomonas
- Nosocomial pneumonia ? patients in hospital
- Pulmonary infections ? cystic fibrosis patients
-
What is the most common cause of respiratory failure in cystic fibrosis patients?
Pseudomonas
-
What is the pathogenesis of cystic fibrosis?
- Mutation in CFTR gene
- Nonfunctional transporter that regulates chloride ions
- Unable to actively pump chloride ions
-
Who is most affected by pseudomonal osteomyelitis
- IV drug users ? directly introduce microbe into blood stream when using needles
- Diabetics ? traumatic injury of foot due to diabetic neuropathy
-
What are the virulence factors of pseudomonas?
-
What is a serious complication of burn injuries?
Pseudomonas
-
Why is pseudomonas a feared complication of burn injuries
- Often fatal
- Unresponsive to antibiotics
-
What is often colonized by nosocomial bacteria
Indwelling catheters
-
What is common clinical presentation of nosocomial pseudomonas infection
Urinary Tract Infection (UTI)
-
What skin lesions can pseudomonas cause
- Pruritic papular pustular folliculitis = hot tub folliculitis
- Ecthyma gangrenosum = toxin mediated cutaneous necrosis
-
Who is at risk of developing pseudomonal folliculitis
People using underchlorinated hot tubs
-
How does pseudomonas cause ecthyma gangrenosum
Exotoxin A
-
What does pseudomonal ecthyma gangrenosum look like
Black necrotic lesions of the skin
-
What is swimmers ear
Pseudomonal otitis externa ? infection of the outer ear
-
What do pseudomonas and Corynebacterium have in common
- Exotoxin A (pseudomonas)
- Diphtheria exotoxin (Corynebacterium diphtheriae)
-
How does pseudomonas exotoxin A work
- Ribosylates elongation factor 2
- Causes inhibition of protein synthesis and cell death
-
How do you treat pseudomonas infection?
- Antipseudomonal penicillin ? piperacillin + tazobactam
- Aminoglycosides (in combination with beta lactams)
- Fluoroquinolones ? UTI
-
What gram stain is Mycobacterium tuberculosis
Does not stain with gram stain
-
How do we visualize Mycobacterium tuberculosis?
Acid fast stain
-
What is acid fast stain
Carbolfuschin
-
Which bacteria are acid fast
- Nocordiae ? partially
- Mycobacterium
-
What does carbolfuschin stain in acid fast bacteria
High concentration of mycolic acids in cell wall
-
What are mycolic acids
Waxy fatty acids with 2 side chains
-
How do we grow Mycobacterium tuberculosis?
- Cultures very slowly (2-6 weeks)
- Lowenstein Jensen media
- obligate aerobe
-
what is Lowenstein Jensen media?
- starch + egg
- things that inhibit growth of other bacteria that may be present in patient?s sputum
-
how is Mycobacterium tuberculosis transmitted?
respiratory droplets
-
where can Mycobacterium tuberculosis grow
facultative intracellular ? in macrophages
-
what is the pathogenesis of Mycobacterium tuberculosis infection?
- infects someone via respiratory droplets
- fails to be cleared immediately by immune system
- primarily resides and proliferates in macrophages
-
what are Mycobacterium tuberculosis virulence factors?
- mycolic acids in cell wall
- chord factor = glycolipids in cell wall
- sulfatides
-
what is the function of the chord factor in Mycobacterium tuberculosis?
protects bacteria from being destroyed by causing granuloma formation
-
what is essential for virulence of Mycobacterium tuberculosis
Chord factor (glycolipids) to allow formation of serpentine like clumps of bacteria
-
What is chord factor of Mycobacterium tuberculosis
Glycolipids found in the cell wall that are involved in clumping of the bacteria into serpentine like formation
-
How does chord factor of Mycobacterium tuberculosis work?
- Increases Tissue Necrosis Factor alpha and other inflammatory cytokines
- This activates other macrophages
- Newly activated macrophages form granuloma
- Bacteria is walled off
-
What is the function of sulfatides in Mycobacterium tuberculosis?
Allows survival of the bacteria inside macrophages
-
How do sulfatides of Mycobacterium tuberculosis work
- Prevent phagolysosome fusion
- Sparing bacteria from exposure to lysosomal hydrolases
- Accumulate in phagosomes and create incompetent secondary lysosomes which are unable to fuse
-
How does Mycobacterium tuberculosis infection progress?
- Primary infection
- 3 different outcomes
- * Healed latent infection
- * Systemic infection = military TB
- * Reactivation of latent TB later in life
-
What does primary Mycobacterium tuberculosis infection cause?
- Affects lower / middle lobe of lung
- Nearby hilar lymph nodes also affected
- After primary lesion heals --> fibrotic --> calcified
-
What is the Ghon complex
Visible calcifications of lung parenchyma + hilar lymph nodes affected by Mycobacterium tuberculosis
-
How can we visualize primary Mycobacterium tuberculosis infection?
Chest x-ray to see Ghon complex
-
What kind of granulomas does Mycobacterium tuberculosis cause?
Caseating granuloma = tubercle
-
Why are granulomas formed
Attempt to wall off infection
-
What do granulomas look like?
Collection of activated macrophages = Langerhans giant cells
-
What are Langerhans giant cells
Activated macrophages found in granulomas
-
What do tubercles of Mycobacterium tuberculosis infection look like
- Langerhans giant cells surrounding a central area of caseating necrosis (caseating granuloma)
- Often developing fibrosis and scarring surrounding granuloma
-
What is the clinical presentation of Mycobacterium tuberculosis primary infection?
Prolonged fever
-
Who is most affected by Mycobacterium tuberculosis primary infection
Children in area endemic to tuberculosis
-
What is the most common path of Mycobacterium tuberculosis infection after primary infection?
Resolves heals by fibrosis and calcification and becomes latent
-
Who has a positive Mantoux test
- Someone after primary infection of Mycobacterium tuberculosis
- Someone with an active infection
- Someone with a latent infection
- Someone who has been vaccinated against Mycobacterium tuberculosis
-
What is PPD
Purified Protein Derivative (PPD)
-
What is the mantoux test
Tuberculin skin test using Purified Protein Derivative (PPD)
-
What does a positive mantoux test look like?
Wheel on skin where TB particles are injected
-
why is there a lump in positive mantoux test?
type 4 (delayed type) hypersentivity reaction to TB particles
-
what is the BCG vaccine?
developed from attenuated Mycobacterium bovis
-
how effective is BCG vaccine in protecting against Mycobacterium tuberculosis?
variable ranging from 0-80% effective
-
what happens in military TB?
- bacteremia --> Mycobacterium tuberculosis can seed in almost any organ of the body
- Acute very dangerous process that can quickly progress to death
-
What organs are most affected in military TB?
-
What is military TB
Systemic spread of Mycobacterium tuberculosis
-
What is the clinical presentation of military TB?
- Depends on the organ affected
- Fulminant multi-organ failure
- Potentially lethal
-
Who is most affected by military TB
Immigrant from Mycobacterium tuberculosis endemic area
-
Who is affected by reactivation of latent TB
- Only in 5 ? 10% people
- Associated with state of immunosuppression ? HIV / old age / cancer
-
How does latent TB become reactivated?
Downregulation of Tissue Necrosis Factor alpha release
-
What is Tissue Necrosis Factor alpha?
Pro inflammatory cytokine that causes Mycobacterium tuberculosis infection to be contained
-
What happens in Mycobacterium tuberculosis infection if TNF alpha is inhibited?
Immune system is defenseless --> uncontained infection
-
What must you do before giving a TNF inhibitor
Screen using mantoux test (PPD) to check for Mycobacterium tuberculosis latent infection
-
What does reactivated Mycobacterium tuberculosis infection affect most commonly
- Upper lobes of lung
- Skeletal system
- CNS
-
What is the clinical presentation of reactivation of TB?
- Cough
- Night sweats
- Hemoptysis = coughing up of blood
- Cachexia = wasting and weight loss
-
Where does reactivation of TB originate from
Within macrophages
-
Why do patients experience cachexia in reactivation of TB?
TNF alpha produced in reaction to chord factor promotes wasting
-
What is Pott?s disease
- Reactivated Mycobacterium tuberculosis infects the spinal column
- Usually multiple vertebrae are affected
-
What is the clinical presentation of Pott?s disease?
- Demineralization of bone with soft tissue swelling
- Pain
- Abscess formation
- Spinal deformities
- Weakness due to loss of support
-
How does CNS involvement of reactivated Mycobacterium tuberculosis manifest?
-
What is a tuberculoma
Cavitary lesion in the brain
-
How do we treat Mycobacterium tuberculosis?
-
Why does Mycobacterium tuberculosis form resistance to drugs easily?
- Treatment period is very long
- RIPE combination therapy
- * R ? Rifampin
- * I ? Isoniazid
- * P ? Pyrazinamide
- * E ? Ethambutol
- Vaccination
-
Why do we use combination therapy to treat Mycobacterium tuberculosis infection?
Prevent drug resistance during long course of treatment form developing
-
What is the treatment as prophylaxis of latent TB?
Rifampin + Isoniazid for 9 months
-
What gram stain is Mycobacterium tuberculosis
- Does not stain with gram stain
- Acid fast
-
How do we visualize mycobacterium leprae?
Acid fast stain ? carbolfuchsin
-
What does carbolfuchsin stain
Mycolic acid ? made of 2 waxy chains
-
How do we grow mycobacterium leprae?
Thrives in cold temperatures
-
Why does mycobacterium leprae infection affect the extremities
Prefers cooler temperatures
-
What is the reservoir for mycobacterium leprae?
Armadillo
-
What does mycobacterium leprae cause
- Leprosy = Hansen?s disease
- Tuberculoid leprosy
- Lepromatous leprosy
-
What is Hansen?s disease
Leprosy caused by mycobacterium leprae
-
What is the clinical presentation of tuberculoid leprosy caused by mycobacterium leprae?
- Relatively mild symptoms
- Well demarcated hairless hypo esthetic skin plaque anywhere on the body
-
What is the helper T cell immune response to tuberculoid leprosy caused by mycobacterium leprae?
- TH1 cells ? promotes cell mediated immunity
- Macrophages engulf the bacteria
-
What is the TH1 immune response
- Promotes cell mediated immunity
- Contains bacteria within macrophages
-
How do we diagnose tuberculoid leprosy caused by mycobacterium leprae?
Lepromin skin test
-
What is a lepromin skin test?
Intradermal injection of mycobacterium leprae antigens to test for presence of immune reaction
-
What is the helper T cell immune response to lepromatous leprosy caused by mycobacterium leprae?
TH2 cells ? promotes humoral response
-
What is the TH2 immune response
Promotes humoral response
-
When does lepromatous leprosy caused by mycobacterium leprae occur
- When body is unable to mount an appropriate cell mediated response
- Unable to contain the mycobacterium leprae in the macrophages
-
How is lepromatous leprosy caused by mycobacterium leprae transmitted?
- Unknown mode of transmission between humans
- Maybe via respiratory droplets
-
What is the clinical presentation of lepromatous leprosy caused by mycobacterium leprae?
- Symmetric neuropathy with glove and stocking pattern
- Numerous poorly demarcated raised lesion often on the extensor surfaces
- Profound fascial deformity ? Leonine facies
-
What is leonine facies
- Profound fascial deformities caused by lepromatous leprosy
- thickening of skin, loss of eyebrows and eyelashes, collapse of nose and formation of nodular ear lobes
-
What would you see on biopsy of lepromatous leprosy skin lesions?
Large amounts of mycobacterium leprae bacteria
-
What would you see on biopsy of tuberculoid skin lesions?
Small amounts of mycobacterium leprae bacteria
-
What is the difference between lepromatous and tuberculoid leprosy caused by mycobacterium leprae?
- 2 opposite ends of a spectrum
- Tuberculoid ? cell mediated immune response
- Lepromatous ? humoral immune response
- Tuberculoid skin lesions ? well demarcated and contain few bacteria
- Lepromatous skin lesions ? poorly demarcated and contain many bacteria
-
How do we treat mycobacterium leprae infection?
Long term multidrug therapy
-
How do we treat tuberculoid leprosy caused by mycobacterium leprae?
Dapsone + Rifampin for 6 months
-
Who do we treat lepromatous leprosy caused by mycobacterium leprae?
- Dapsone + Rifampin + Clofazimine for 2-5 years
- Deformities and neuropathies may not be reversible
-
What gram stain are actinomycetes
Gram + branching rod (filamentous)
-
What species are in actinomyces genus
Actinomyces Israeli
-
What conditions do we grow actinomyces Israeli in?
Obligate Anaerobic
-
Where is actinomyces found
Normal flora of the oral cavity
-
In what situation do actinomyces infections occur
After jaw trauma (dental procedures)
-
Where does actinomyces infection spread
From oral cavity --> head and neck
-
What infections are caused by actinomyces
Cervical facial actinomyces infection
-
What does cervical fascial actinomyces infection look like
- Begins with non-tender lump in jaw --> abscess --> sinus tracks that drain infection site through the skin
- Thick yellow pus
-
Why is pus from actinomyces infection yellow
Characteristic yellow sulfur granules
-
How do you treat actinomyces infection?
- Penicillin G
- Surgical drainage of complicated infections
-
What gram stain is Nocardiae
- Gram + filamentous branching rods
- Weak acid fast
-
What species are in the Nocardiae genus
Nocardiae asteroids
-
What conditions do we grow Nocardiae in?
Obligate aerobe
-
How do we tell the difference between actinomyces and nocardiae?
- Obligate anaerobe (actinomyces)
- Obligate aerobe (Nocardiae)
- Weak acid fast (Nocardiae)
-
what are the gram + filamentous branching rods?
-
where can nocardiae be found
in the soil
-
what bacteria can be found in the soil
- clostridium tetani (spore)
- clostridium perfringens (spore)
- nocardiae (gram + rod)
-
what is the acid fast technique of staining?
carbolfuchsin stain taken up when bacteria have mycolic acids in their cell walls
-
what are mycolic acids
long chained fatty acids with 2 tails
-
why are nocardiae weakly acid fast
contain mycolic acid in their cell walls
-
What biochemical markers do nocardiae have?
-
Which patients are most susceptible to catalase positive organisms
Patients with Chronic Granulomatous Disease
-
Which bacteria are patients with CGD most susceptible to
- Chronic Granulomatous Disease ? catalase + organisms
- * SPACE, nous voyons notre chat, gros petit tresor, houra!
- * Staphylococci
- * Pseudomonas aeruginosa
- * Aspergillus fumigatus
- * Candida
- * Enterobacteriaceae
- * Neisseria
- * Vibrio
- * Nocardiae
- * Campylobacter
- * Helicobacter
- * Gardnerella vaginalis
- * Pseudomonas cepacia
- * Mycobacterium Tuberculosis
-
what infections does nocardiae cause
- pulmonary ? pneumonia with lung abscess formation
- CNS ? brain abscesses
- Cutaneous
-
Who is most affected by nocardiae infections
- Immunocompromised Men with impaired cell mediated immunity
- * HIV
- * Transplant
- * Glucocorticoids
- More common in men than women
-
How does pulmonary nocardiosis manifest
Pneumonia with lung abscess formation (cavitary lesions)
-
Where does nocardiae spread after infecting lungs
- CNS
- Can go anywhere in body
-
Why does nocardiae cause CNS infections
Nocardiae has affinity for neural tissue
-
How does CNS nocardiosis manifest
Brain abscesses
-
How is cutaneous nocardiosis transmitted
Open wounds exposed to dirt
-
How does cutaneous nocardiosis manifest
Pyogenic (inflammatory) response with production of indurated lesions
-
How do you treat nocardiosis?
Sulfonamides
-
What does clostridium tetani cause
Tetanus
-
What gram stain is clostridium
Gram + rod
-
What conditions do clostridia need to grow?
Obligate anaerobes ? cannot survive in presence of oxygen
-
Which bacteria are spore forming
- Clostridia genus
- Bacillus genus
-
Where is clostridium tetani spores often found
Soil
-
How can clostridium tetani cause infection
- Must get under the skin into an anaerobic environment
- e.g. under a puncture wound closed off to air
-
what kind of wounds are classically associated with clostridium tetani infection?
- puncture wound closed off to air
- e.g. by rusty nails or barbed wire
-
what are the symptoms of tetanus?
- spastic paralysis
- risus sardonicus
- lockjaw
- opisthotonus
-
what does spastic paralysis look like?
patients experience relentless muscle contractions leading to rigidity
-
what are the symptoms of botulism?
flaccid paralysis
-
what does risus sardonicus mean
evil smile
-
what is lockjaw
tense masseters prevent the jaw from opening
-
what is opisthotonus
characteristic extension and arching of the back due to powerful spasms of the back muscles
-
what is the pathogenesis of clostridium tetani?
puncture wound with foreign object with tetani spores on it --> spores are embedded in flesh --> organism vegetates and stays at wound site --> organism releases tetanus toxin --> symptoms occur
-
what toxins does clostridium tetani produce?
tetanospasmin
-
what causes the symptoms of tetanus
tetanospasmin released by the clostridium tetani
-
how does tetanospasmin travel in the body
- retrograde through motor axons --> spinal cord
- i.e. from the periphery --> spinal cord
-
how does tetanospasmin work
- acts as a protease
- cleaves SNARE proteins --> inhibits exocytosis of neurotransmitter into synapse --> neurotransmitters remain in vesicles
-
what kinds of neurons release gabba and glycine?
- inhibitory
- e.g. Renshaw cells
-
which types of neurotransmitters does tetanospasmin affect
inhibits released of gabba and glycine (inhibitory neurotransmitters) --> decreased inhibition
-
what do Renshaw cells do?
sense over activity of nearby motor neurons (tetanus) --> fire --> inhibit overactive neuron
-
what neurons are inhibited by tetanospasmin
Renshaw cells
-
What kind of vaccine is tetanus vaccine?
Toxoid vaccine
-
What is a toxoid vaccine?
Toxin conjugated to a protein to increase immunogenicity
-
What is the antibody response created by the tetanus vaccine?
- Antibody response to the toxin
- NOT to the organism
-
What does clostridium botulinum cause?
Botulism
-
What gram stain is clostridium botulinum
Gram + rod
-
Where is clostridium botulinum commonly found?
- Improper canning of foods ? flourish of bacteria
- Honey ? spores
-
Why is clostridium botulinum able to grow in canned foods?
Improper or insufficient heating cycles when canning food --> survival of spores --> spores germinate + flourish in anaerobic environment --> toxin is produced (heat stable)
-
What toxin does clostridium botulinum produce?
Relatively heat stable botulinotoxin
-
why is it important to cook canned food thoroughly?
denatures the relatively heat stable botulinotoxin produced in canned foods
-
what are the symptoms of botulism?
- descending flaccid paralysis ? absence of muscle contraction
- diplopia / ptosis of eyes in eyes
- floppy baby syndrome in babies
-
what is flaccid paralysis
absence of muscle contraction
-
How do you tell the difference between flaccid paralysis in botulism and Guillain-Barre syndrome?
- Botulism
- Descending paralysis (i.e. starts superiorly --> inferiorly)
- Affects multiple family members who have all eaten the same canned food
- Guillain-Barre syndrome
- ascending paralysis (i.e. starts inferiorly --> superiorly)
- very unusual for multiple people to present with the same symptoms
-
transmission of botulism in adults
bacteria grow and reproduces in anaerobic conditions of canned foods --> toxin is formed in food --> preformed toxin absorbed into the gut --> blood --> peripheral nervous system
-
which nervous system does botulinotoxin affect and why
- peripheral nervous system
- toxin is unable to cross the blood brain barrier
-
how does botulinotoxin work
protease that cleaves the SNARE protein --> prevents fusion of vesicles with presynaptic nerve terminal
-
what is the difference between tetanospasmin and botulinotoxin?
- tetanospasmin ? inhibitory Renshaw cells
- botulinotoxin ? motor neurons
-
which types of neurotransmitters does botulinotoxin affect
inhibits released of acetylcholine (excitatory neurotransmitters) --> decreased excitation
-
what kind of neurons release acetylcholine?
excitatory neurons
-
what kind of neurons are inhibited by botulinotoxin?
motor neurons
-
transmission of botulism in babies
honey contains many spores of clostridium botulinum which can flourish in the babies? gut
-
what is floppy baby syndrome
flaccid paralysis caused by botulinotoxin in newborn
-
what is the differences between adult and baby botulism?
- adult ? toxin is pre-formed in canned food anaerobic environment
- baby ? toxin is formed by bacteria in the gut releasing toxin in the gut
-
why is ingestion of clostridium botulinum spores not a risk for adults
normal gut flora outcompete it so there is no germination of spores
-
why is ingestion of clostridium botulinum spores dangerous to babies?
- GIT of babies is a perfect anaerobic environment
- No gut flora to compete with it
- Spores germinate + produce toxin in the gut
-
What is the most common form of botulism and why?
- Floppy baby syndrome
- Honey contains many spores (canned foods are less commonly infected for adults)
-
What gram staining is Clostridium difficile
Gram + rods
-
What does Clostridium difficile cause
Nosocomial diarrhea (pseudomembranous colitis)
-
What does nosocomial mean
People are affected while hospitalized
-
Why is clostridium difficile a nosocomial infection
Spores are easily transferred from patient to patient
-
How can you prevent passing clostridium difficile spores from patient to patient?
- Quick wipe-down with alcohol will not work
- MUST thoroughly wash with soap and water
-
Why Is clostridium difficile unable to infect normal individuals
Clostridium difficile is not good at competing with normal gut flora
-
Why is clostridium difficile able to infect hospitalized patients
- Hospitalized patients often take antibiotics which can wipe-out the normal gut flora
- This means spores are able to germinate and grow in the cleared gut
-
Which antibiotics are most associated with clostridium difficile infections
Clindamycin
-
What causes the symptoms of clostridium difficile infection
Toxin
-
How is clostridium difficile commonly transmitted
Improper handwashing by healthcare providers
-
What toxins does clostridium difficile produce?
-
What does exotoxin A do
Binds to the brush border of intestine
-
What does exotoxin A cause
- Inflammation
- Cell death
- Watery diarrhea
-
What does exotoxin B do?
Disrupts cytoskeleton integrity by depolymerizing actin
-
What does exotoxin B cause?
- Enterocyte death
- Necrosis
- Yellowish grey exudate --> pseudo membrane covering colonic mucosa
-
Why do we call Clostridium difficile infection pseudomembranous colitis?
Pseudo membrane covering the colonic mucosa is formed by exotoxin B action
-
How do you diagnose clostridium difficile infection?
- Visualize pseudo membrane directly either histologically or endoscopically
- Look for toxins in the stool using various assays (usually PCR)
- Do NOT look for organism
-
Why is detecting clostridium difficile in the stool not a good method of diagnosis for infection
Almost 1/3 patients are colonized by the bacteria without any toxins being released to cause infection
-
Why do we diagnose clostridium difficile using toxins?
Only toxin producing strains cause infections
-
How do we treat clostridium difficile infection?
- Oral vancomycin
- Metronidazole
-
Why do we treat clostridium difficile with oral vancomycin (and not IV)?
- Clostridium difficile bacteria are in the gut so it is better to deliver the drug to the site directly
- Vancomycin has poor absorption so there will be fewer side effects
-
What gram staining is clostridium perfringens
Gram + rod
-
In what situations do we see clostridium perfringens infections
- Motorcycle accidents
- deep penetrating wounds from military combat
- i.e. when a large amount of flesh is exposed to dirt or dust
-
where are clostridium perfringens spores commonly found
dirt and soil
-
what conditions does clostridium perfringens need to grow?
obligate anaerobe
-
what does clostridium perfringens cause?
- gas gangrene ? soft tissue infection (clostridial myonecrosis)
- food poisoning
-
what is the other name for clostridial myonecrosis and why?
Gas gangrene ? in the disease process gas is produced under the infected tissue
-
in what situation does clostridial myonecrosis occur
when clostridium perfringens enters a wound and causes infection
-
what are the clinical presentations of gas gangrene?
crepitus / crackling sound on palpation
-
why is gas produced in clostridial myonecrosis?
clostridium perfringens consumes carbohydrates and releases gas
-
what toxins does clostridium perfringens produce?
alpha toxin
-
what does alpha toxin cause?
necrosis
-
how does the alpha toxin of clostridium perfringens work?
- it is a lecithinase
- cleaves lecithin phospholipase --> damage lipoproteins --> damage of cell membranes --> hemolysis of RBC
-
what are the hemolytic properties of clostridium perfringens?
forms a double zone of hemolysis on blood agar
-
why is clostridium perfringens hemolytic?
alpha toxin
-
how do you differentiate clostridium perfringens from other hemolytic bacteria?
MUST be cultured anaerobically so would not grow anaerobically
-
How do you treat clostridium perfringens gas gangrene?
IV penicillin G
-
What are the symptoms of food poisoning caused by clostridium perfringens?
Late onset diarrhea
-
Why is clostridium perfringens diarrhea late onset?
Caused by ingestion of many spores which must germinate in the gut THEN produce toxin whilst in the gut
-
how does clostridium perfringens cause food poisoning?
ingestion of spores --> germination in gut --> bacteria flourish --> toxin is produced
-
how do you treat clostridium perfringens diarrhea?
usually transient so does not require antibiotic treatment
-
What Gram stain and shape are Bacilli
Gram + Rods
-
What species are in the Bacillus genus
- Bacillus anthracis
- Bacillus Cereus
-
What does a black eschar look like?
Black necrotic cutaneous lesion with surrounding erythematous ring
-
What does Bacillus anthracis usually look like under microscope?
Large gram + rods in chains
-
What is the capsule of bacilli made of?
Protein ? poly D glutamate
-
What conditions do bacillus anthracis need to survive?
Obligate aerobe ? only survive in the presence of oxygen
-
Why is bacillus anthracis able to be weaponized?
Forms spores
-
What does a spore allow the bacteria to do?
- hibernate in a state without any significant metabolic activity
- sturdy protective covering means it is highly resistant to temperature and chemicals
- able to survive an extremely long time in almost any external environment
- small and durable
- grow back into metabolically active state when the environmental conditions are favorable
-
which bacteria produce spores
- bacillus genus
- clostridium genus
-
what do spores do when they are in environmentally favorable conditions
revert back to a metabolically active state
-
what toxins does bacillus anthracis produce?
- lethal factor
- edema factor
-
which toxin must be present to cause symptoms in bacillus anthracis infection
both lethal factor and edema factor
-
how does edema factor of bacillus anthracis work?
acts as an adenylate cyclase --> increases cAMP intracellularly --> fluid goes into intracellular space --> edema
-
how does edema benefit the bacillus anthracis bacteria?
- inhibits host defenses
- indirectly prevents phagocytosis
-
how does lethal factor of bacillus anthracis work?
exotoxin that acts as a protease --> cleaves MAP kinase (signal transduction protein)
-
what is MAP kinase
- signal transduction protein
- involved in control of cell growth
- ultimately is responsible for tissue necrosis
-
what does lethal factor of bacillus anthracis cause?
tissue necrosis --> black escar
-
what diseases does bacillus anthracis cause?
- black escars
- pulmonary anthrax = wool sorter?s disease
-
where are the spores of bacillus anthracis often found and why?
- soil --> wool /hide of animals
- can survive for long periods of time
-
how do people get pulmonary anthrax?
inhale anthrax spores (e.g. when handling wool of sheep) --> spores germinate in lungs
-
what are the symptoms of pulmonary anthrax?
- starts as nonspecific pulmonary symptoms (dry cough)
- progresses to hemorrhagic mediastinitis
-
why is it important to catch and treat anthrax early?
bacillus anthracis can rapidly move to mediastinal lymph nodes --> hemorrhagic mediastinitis
-
what are the symptoms of hemorrhagic mediastinitis?
- pulmonary hemorrhage
- widened mediastinum on chest X ray
-
what is the mortality rate once anthrax pulmonary hemorrhage has developed?
almost 100%
-
how do we treat bacillus anthracis?
- drug of choice: fluoroquinolones
- secondary treatment: doxycycline
-
what conditions does bacillus cereus need to grow?
aerobic
-
what diseases does bacillus cereus cause?
food poisoning
-
how do we get bacillus cereus food poisoning?
eating reheated fried rice
-
what are the symptoms of bacillus cereus food poisoning?
vomiting and maybe diarrhea
-
What gram stain is Leptospira interrogans
Doesn?t stain with gram stain (spirochete)
-
How do we visualize Leptospira interrogans?
You can?t with a light microscope
-
What does Leptospira interrogans infection cause
Leptospirosis
-
Where is Leptospira interrogans infection endemic
Tropical regions
-
What is Leptospira interrogans shape
- Spirochete
- Question mark shaped
-
Where can we find Leptospira interrogans
Rodents / dogs
-
How is Leptospira interrogans transmitted
- Excreted in animal?s urine
- Transmitted to humans when they swim in contaminated water
-
Who is most affected by Leptospira interrogans infection
People who take part in water sports
-
What is the clinical presentation of Leptospira interrogans infection?
- Flu like symptoms ? fever + intense headaches
- Conjunctival suffusion ? diffuse reddening of the eyes with no inflammatory exudate
- Weil?s disease ? renal dysfunction and jaundice
-
What is the difference between conjunctivitis and conjunctival suffusion?
No inflammatory exudate in conjunctival suffusion
-
What is Weil?s disease
- Caused by Leptospira interrogans
- Renal dysfunction
- Jaundice from liver damage
-
What is the pathogenesis of Leptospira interrogans infection?
- Travels through bloodstream
- Multiplies in various organs ? kidneys / liver
-
Which organs does Leptospira interrogans affect most commonly
-
How do we test for renal dysfunction?
- High creatinine levels
- Azotemia
-
What gram stain is Treponema pallidum
Doesn?t stain with gram stain (spirochete)
-
How do we visualize Treponema pallidum?
Can?t be visualized using light microscopy
-
What does Treponema pallidum cause?
Syphilis (STD)
-
How is Treponema pallidum transmitted?
Sexually transmitted disease
-
What causes syphilis
Treponema pallidum
-
Why is syphilis called ?the great imitatorjQuery110104336385577609254_1485168348375
Many of the symptoms look like many other diseases
-
What are the most common sexually transmitted diseases?
- Chlamydia (Chlamydia trachomatis)
- Gonorrhea (Neisseria Gonorrheae)
-
How is Treponema pallidum visualized?
Dark field microscopy
-
How do we collect a sample for Treponema pallidum visualization?
Direct sample from a lesion on a patient
-
Why is direct visualization of Treponema pallidum not commonly used?
Dark field microscopy is time consuming and not all labs are equipped to use it
-
How do we diagnose syphilis caused by Treponema pallidum?
- Dark field microscopy
- Blood tests
- * VDRL ? screening
- * RPR ? screening
- * FTA-Ab ? confirmatory
-
What is the mean screening test for Treponema pallidum?
- Venereal Disease Research Laboratory (VDRL)
- Rapid Plasmin Reagent Test (RPR)
-
What is the VDRL
- Venereal Disease Research Laboratory
- Non Treponema test (for syphilis)
- Tests for antibody reactivity in patient?s serum to a cardiolipin cholesterol lecithin antigen
-
What does VDRL test for
Antibody reactivity to cardiolipin cholesterol lecithin
-
Who do we screen for syphilis?
- Patients with symptoms
- Patients at high risk
-
Why do we get false positives in VDRL and RPR?
- Cross reactivity with other antigens
- * Mononucleosis (Epstein Barr Virus)
- * Rheumatoid factor (autoimmune)
- * Systemic Lupus Erythematosis (autoimmune)
- * Leprosy (Mycobacterium leprae)
- * IV drug users
-
What is the confirmation test for Treponema pallidum infection?
- FTA Antibody test (FTA-Ab)
- Treponemal test
- Tests for antibodies directly against Treponema pallidum
-
What does FTA-Ab test for
Tests for antibodies directly against Treponema pallidum
-
When do we perform FTA-Ab test?
Used after non-treponemal tests show reactivity
-
What are the stages of syphilis caused by Treponema pallidum?
- Early stage ? first year
- * Primary
- * Secondary
- * Early latent
- Late stage
- * Tertiary
- * Late latent
-
What is the clinical presentation of primary syphilis caused by Treponema pallidum?
Painless genital chancre that appears a few weeks after inoculation and heals in 3-6 weeks
-
How does Treponema pallidum cause genital chancres?
- Locally invading small blood vessels and damaging them
- Causes small areas of ischemic necrosis --> chancre
- Also ischemic nerve damage
-
When does syphilis progress to the secondary stage
When chancre is left untreated (because it is painless)
-
What is the clinical presentation of secondary syphilis caused by Treponema pallidum?
- Systemic disease
- Maculopapular rash everywhere including palms of hands and soles of feet that occurs weeks to months after infection
- Condyloma lata
-
Which STD causes rash to appear on the hands and soles of feet
Syphilis ? Treponema pallidum
-
What causes condyloma lata and what does it look like
- Treponema pallidum
- Flat topped bumps on mucous membranes
-
What causes condyloma acuminata and what does it look like
- Human Papilloma Virus
- Wart like
-
How can you visualize the pathogen in condyloma lata?
Dark field microscopy to see spirochete Treponema pallidum
-
What is the clinical presentation of tertiary syphilis caused by Treponema pallidum?
- Gomas = soft growths with firm necrotic center
- Aortitis (of ascending thoracic aorta) --> ascending thoracic aneurysm
- Tabes dorsalis = demyelination of nerves in posterior column
- argyll robertson pupil = accommodate but do not react to light
-
What are gomas and what causes them
- Treponema pallidum in tertiary syphilis
- Soft growths with firm necrotic center that can occur anywhere
-
What are the complications of aortitis caused by tertiary syphilis?
- Aneurysm
- Aorta demonstrates tree barking (thick + wrinkled)
-
How does syphilis cause aortic aneurysm?
- Targets vasa vasorum which supply wall of aorta --> weakening of aortic wall --> aneurysm formation
- Similar to small vessel damage --> chancre in primary syphilis
-
What is tabes dorsalis and what causes it
- Treponema pallidum in tertiary syphilis
- Demyelination of nerves in the dorsal / posterior columns of the spinal cord
-
What is the clinical presentation of tabes dorsalis in tertiary syphilis?
- Loss of vibration sense
- Propriosense --> off gait
- Discriminative touch
- lancinating pain ? piercing / stabbing pain
-
what is argyll robertson pupil and what causes it
- Treponema pallidum in tertiary syphilis
- Accommodate but do not react to light
-
Why is congenital syphilis not as common nowadays?
Standard screening of pregnant women
-
What is the clinical presentation of congenital syphilis?
- Constellation of symptoms in children
- Saber shins = anterior bowing of tibia
- Saddle shaped nose
-
What are saber shins and what infection can cause them?
- Congenital syphilis
- Anterior bowing of the tibia
- Hutchinson?s teeth ? notched incisors
- Mulberry molars ? molars with several enamel outgrowths
- Congenital deafness
-
How do we treat syphilis caused by Treponema pallidum?
- Penicillin in every stage and in everyone
- Should desensitize allergic patients and still use penicillin
-
Why can?t we use tetracycline in pregnancy?
Affects teeth and bond growth
-
What is the Jarisch Herxheimer reaction
Fever / chills / headache that occurs within hours of starting penicillin treatment against Treponema pallidum in syphilis
-
What causes the Jarisch Herxheimer reaction
- Treatment of patient with syphilis using penicillin causes huge spirochete death
- Dyeing spirochetes release a bunch of Lipopolysaccharide --> increase in cytokines
-
What is a good indicator that penicillin treatment is working in syphilis?
Fever / chills / headache of Jarisch Herxheimer reaction
-
What gram stain is Legionella pneumophila
- Gram ? thin pleomorphic
- Does not take up gram stain very well
-
How do we visuals Legionella pneumophila
Silver stain
-
How do we grow Legionella pneumophila?
- Buffered charcoal yeast extract
- In the presence of cysteine and iron
-
What does Legionella pneumophila infection cause
- Legionnaire?s disease ? very serious + potentially fatal
- Pontiac fever ? less serious
-
What is the clinical presentation of Pontiac fever caused by Legionella pneumophila?
- Fever
- Malaise
- Self-limited
-
Who is most affected by legionnaire?s disease caused by Legionella pneumophila
Smokers
-
What bacteria cause atypical pneumonia
- Legionella pneumophila
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
-
What does atypical pneumonia caused by Legionella pneumophila look like on chest X-ray
- Patchy infiltrate with consolidation of one lobe
- Highly variable and can easily be mistaken for another type of pneumonia
-
What is the clinical presentation of legionnaire?s diseases caused by Legionella pneumophila?
- Atypical pneumonia
- Hyponatremia (<130mmol/L)
- Neurologic symptoms ? headache with confusion
- Diarrhea
- High fever (>40oC)
-
Which bacteria causes pneumonia with diarrhea and hyponatremia
Legionella pneumophila
-
How do we diagnose legionnaire?s disease caused by Legionella pneumophila?
- Culture respiratory sputum ? 3-5 days
- Rapid urine antigen test
-
How do we treat legionnaire?s disease caused by Legionella pneumophila?
- Macrolides
- Fluoroquinolones ? have fewer complications than macrolides
-
How do we treat atypical pneumonia?
Macrolides
-
How do we treat Pontiac diseases caused by Legionella pneumophila?
We don?t ? it is self-limited
-
What biochemical properties does Legionella pneumophila have?
Oxidase +
-
What gram stain are Borreliae
Don?t gram stain (spirochete)
-
What are spirochetes
Bacteria that are spiral shaped
-
Which bacteria are spirochetes
- Borrelia
- Leptospira
- Treponema
-
What does Borrelia burgdorferi cause
Lyme disease
-
Where do we commonly find Borrelia burgdorferi
Northeastern united states
-
Who is affected by Borrelia burgdorferi
- People who were on hiking or camping trips
- Hunters
-
How is Borrelia burgdorferi transmitted
- Tick born disease
- ixodes scapularis tick
-
what diseases does the ixodes scapularis tick transmit?
- Lyme disease (Borrelia burgdorferi)
- Ehrlichiosis (ehrlichiae genus / Anaplasma genus)
- Babesiosis (Protozoa Babesia)
-
Where can we find Ixodes scapularis larvae
White footed mouse
-
Where can we find adult Ixodes scapularis
White tailed deer
-
What is the main reservoir for Ixodes scapularis?
White footed mouse
-
What is an obligatory host for Ixodes scapularis?
White tailed deer
-
What is the vector for Borrelia burgdorferi infection?
Ixodes scapularis tick
-
What are humans in the life cycle of the Ixodes scapularis tick
Incidental dead end host
-
Why don?t spirochetes gram stain
Have very thin walls
-
How do we visualize Borrelia burgdorferi?
- Wright stain
- Giemsa stain
-
Which spirochete are we able to visualize under light microscope
Borrelia burgdorferi
-
What is the clinical presentation of Borrelia burgdorferi infection?
- 3 stages
- 1. Erythema chronica migrans
- 2. Heart block caused by myocarditis + bilateral fascial nerve palsy
- 3. Migratory polyarthritis + Encephalopathic effects
-
What does erythema chronica migrans in Borrelia burgdorferi infection look like
- Bulls eye rash
- Not painful
- Not puritis
- Flu like symptoms
-
What is the name for the bull?s eye rash you get in Borrelia burgdorferi infection?
Erythema chronica migrans
-
When do we see erythema chronica migrans?
One month after tick bite infected with Borrelia burgdorferi
-
What is bell?s palsy
Idiopathic fascial nerve palsy
-
What is the second stage of Borrelia burgdorferi infection?
- Heart block caused by myocarditis
- Bilateral fascial nerve palsy
-
What is the clinical presentation of migratory polyarthritis caused by Borrelia burgdorferi infection?
- Arthritis of large joints (e.g. knee)
- Many joints can be affected
- Can move from joint to joint
-
What are the CNS effects of Borrelia burgdorferi infection?
- Subtle Encephalopathy
- Memory difficulty
- Cognitive slowing
- Lymphocytic meningitis
-
How do we treat Borrelia burgdorferi infection?
- As early as possible
- Doxycycline ? in stage 1
- Ceftriaxone ? later presentation
-
Which species are in the Rickettsiae genus
- Rickettsia prowazekii
- Rickettsia rickettsii
-
Where can Rickettsiae grow
Obligate intracellular ? unable to produce NAD+ and CoA
-
What gram stain are Rickettsiae
- Does not take up gram stain very well
- Gram ? coccobacillus
-
How do we visualize Rickettsia?
Giemsa stain
-
Why are Rickettsiae obligate intracellular
- Unable to produce NAD+ and CoA
- Both are needed for bacterial growth and replication
- Get them form eukaryotic cells instead
-
What is the Weil Felix test?
- Agglutination test to diagnose Rickettsial infections
- Tests for cross reactivity between Rickettsia species and Proteus Vulgaris
- Not very sensitive or specific
-
What are the general prodromal symptoms of a Rickettsial infection?
- Headache
- Fever
- Vasculitis
-
Which vessels are affected by vasculitis in Rickettsial infection
Thin blood vessels of capillary beds
- What is the clinical presentation of vasculitis caused by Rickettsial infections?
- Granular bumpy rash
-
How do we treat Rickettsiae infections?
Tetracycline ? doxycycline
-
What is the clinical presentation of epidemic typhus caused by Rickettsia prowazekii?
- Rash that starts at trunk and spreads to extremities
- Rash spares hands, feet and head
- Myalgia + arthralgia
- Pneumonia
- Encephalitis with dizziness and confusion
- Coma
-
Who is most affected by Rickettsia prowazekii
- Anyone living in close quarters (e.g. military or prisoners)
- Poor hygiene
-
How is Rickettsia prowazekii transmitted
Arthropod vectors ? lice
-
Why are lice a good vector for spreading of Rickettsia prowazekii
- Feed on human blood
- Defecates near feeding site
- Scratching --> introduction of bacteria into blood stream
-
What does Rickettsia prowazekii infection cause
Epidemic typhus
-
What is the difference between Rickettsia prowazekii and Rickettsia typhi?
- Epidemic typhus (prowazekii)
- Endemic typhus (typhi)
-
What does endemic mean
disease localized to a region that doesn?t necessarily comment on magnitude of population getting illness
-
what does epidemic mean
wide spread rampant outbreak
-
what does Rickettsia rickettsii cause
rocky mountain spotted fever
-
how is Rickettsia rickettsii transmitted
arthropod vectors ? dermacentor tick
-
how do dermacentor ticks transmit Rickettsia rickettsii infection
direct biting
-
what is the clinical presentation of rocky mountain spotted fever caused by Rickettsia rickettsii?
- incubation period ranging from 2-14 days
- rash starts at ankles and wrists --> central
- rash covers hands and feet in later stages of disease
- headache
- fever
- myalgia ? sever muscle pain
-
What does Coxiella burnetii infection cause
Q fever
-
What gram stain is Coxiella
Gram ? coccobacillus
-
What is the clinical presentation of Q fever caused by Coxiella burnetii?
No rash
-
Where can we fine Coxiella burnetii
Obligate intracellular
-
How is Coxiella burnetii able to survive digestive tracts of animals
Forms a sturdy spore like structure
-
Where can we find Coxiella burnetii ?spores?
In animal droppings in dirt
-
How is Coxiella burnetii transmitted
Aerosol transmission
-
What is a major reservoir for Coxiella burnetii?
Farm animals
-
Who is most affected by Coxiella burnetii
- Farmers
- Veterinarian that has just delivered a baby animal and was exposed to placental excretions
-
What is the clinical presentation of Q fever caused by Coxiella burnetii?
- Pneumonia
- Headache
- Fever
- Hepatitis
-
How do you tell the difference between Q fever (Coxiella burnetii) and Brucellosis?
- Brucellosis ? undulating fever
- Both have pneumonia and hepatitis symptoms
-
How do you treat Q fever caused by Coxiella burnetii?
- Usually self-limiting ? goes away within 2 weeks
- Pasteurizing milk kills most organisms
- Vaccine
-
Who can get chronic Q fever caused by Coxiella burnetii
- Immunocompromised patients
- Patients with previous valvular damage
-
What is the clinical presentation of chronic Q fever caused by Coxiella burnetii?
Endocarditis
-
What kind of vaccine is Coxiella burnetii vaccine?
Acellular
-
Who gets the Coxiella burnetii vaccine
- Veterinarians
- Other high risk people ? farmers
-
What species are in the Bartonella genus
Bartonella henselae
-
What does Bartonella henselae cause
- Cat scratch fever
- Bacillary angiomatsosis
-
What gram stain are Bartonella
Gram ? rod
-
How do we visualize Bartonella henselae?
Warthin starry stain ? type of silver stain
-
What is the Warthin starry stain?
Type of silver stain used to stain Bartonella henselae
-
What is the clinical presentation of cat scratch disease caused by Bartonella henselae?
- Fever
- Painful large lymph nodes in axilla ? lymphadenitis
-
How is Bartonella henselae transmitted
Cat scratches or bites
-
Who is affected by cat scratch disease caused by Bartonella henselae
Immunocompetent healthy people
-
Who is affected by bacillary angiomatosis caused by Bartonella henselae
- Immunocompromised people
- HIV infected patients
-
What is the clinical presentation of bacillary angiomatosis caused by Bartonella henselae?
- Fever chills headaches
- Raised red vascular legions all over skin
-
What is similar between Kaposi sarcoma and bacillary angiomatosis
- Immunocompromised patients ? HIV
- Red vascular lesions on skin
-
How do you differentiate between Kaposi sarcoma and bacillary angiomatosis caused by Bartonella henselae?
Skin biopsy stained with Warthin starry silver stain
-
How do you treat bacillary angiomatosis caused by Bartonella henselae?
- Doxycycline
- Macrolides ? azithromycin
-
How do you treat cat scratch disease caused by Bartonella henselae?
- Usually self-limited so don?t treat
- Azithromycin ? if swelling and pain from lymph nodes too severe
-
What species are in the chlamydia genus
- Chlamydia trachomatis
- Chlamydophila pneumoniae
- Chlamydophila psittaci
-
How is chlamydia transmitted
Sexually transmitted disease
-
Where can chlamydia grow
Obligate intracellular bacteria
-
What gram stain are chlamydia
No staining with gram stain
-
What do chlamydiae and rickettsia have in common
- Both obligate intracellular organisms ? can?t create their own ATP
- Both stain poorly with gram stain
-
Why are chlamydia obligate intracellular organisms?
Cant create own ATP
-
What is special about chlamydia cell wall
Does not have muramic acid
-
What is muramic acid
Part of peptidoglycans that make up the cell wall
-
What is the life cycle of chlamydia?
- Elementary bodies
- Reticular bodies
-
What is the elementary body of chlamydia?
- 1st stage of life cycle
- Found outside of cell
-
What is the reticular body of chlamydia?
- 2nd stage of life cycle
- Found inside the cell
-
Where and how do chlamydia multiply
- Inside cells
- By binary fission
-
Which form of chlamydia is the active form
- Reticular body
- Able to multiply
-
How are newly formed chlamydia released from cells
In their elementary form
-
Which form of chlamydia is the infectious form
Elementary body
-
How do we visualize chlamydia?
- Giemsa stain
- See inclusion bodies in cells infected with chlamydia under the microscope
-
What are chlamydia inclusion bodies?
- Bunches of reticular cells dividing inside the cell
- What do we use Giemsa stain to visualize?
- Chlamydia
- Borrelia
-
How do we diagnose chlamydia infection?
Nucleic Acid Amplification test (NAAT)
-
What is NAAT
- Nucleic Acid Amplification Test
- Basically PCR
-
What serovars are there in chlamydia trachomatis species
-
what is the most common bacterial STD in USA?
chlamydia trachomatis D-K infection
-
what does chlamydia trachomatis D-K cause?
sexually transmitted disease
-
what is the clinical presentation of chlamydia trachomatis D-K infection?
- symptoms vary / remain asymptomatic
- watery discharge
- can progress ? Pelvic inflammatory disease
-
what is the difference between chlamydia and gonorrhea?
- Chlamydia ? watery discharge (chlamydia trachomatis D-K)
- Gonorrhea ? mucopurulent white discharge (Neisseria gonorrhea)
- Chlamydia ? congenital conjunctivitis after 1st week of life
- Gonorrhea ? congenital conjunctivitis within first 2-4 days of life
-
What is pelvic inflammatory disease
Ascending infection that can lead to cervicitis, salpingitis, pelvic pain, abscess formation, scarring of the tubes that can lead to infertility / atopic pregnancies later in life
-
Why is it important to treat STDs as soon as possible ]
To avoid progression to pelvic inflammatory disease and its complications (including infertility / atopic pregnancies)
-
What do congenital chlamydia trachomatis D-K infection cause
- Neonatal conjunctivitis
- Neonatal pneumonia
-
How does congenital chlamydia D-K occur
When mother gives birth whilst with an active infection
-
What is the clinical presentation of chlamydia trachomatis D-K congenital conjunctivitis
Conjunctivitis occurs after first week of life
-
What is the clinical presentation of chlamydia trachomatis D-K pneumonia
Staccato cough ? cough with short sudden bursts
-
What is the most common serovar to cause chlamydia STD?
D-K
-
What do chlamydia trachomatis L1-L3 cause?
Lympho Granuloma Venereum (LGV)
-
What is LGV caused by chlamydia trachomatis L1-L3
- Lymphogranuloma venereum
- Infection of the inguinal lymph nodes
-
What is the clinical presentation of chlamydia trachomatis L1-L3 lymphogranuloma venereum?
- Starts as painless genital ulcer (like syphilis)
- Tender lymphadenopathy with draining lymph nodes weeks-months later
-
What do chlamydia trachomatis A-C cause?
Trachoma
-
What is the leading cause of blindness in the world?
Trachoma caused by chlamydia trachomatis serovars A-C
-
How are chlamydia trachomatis A-C transmitted?
- Hand to eye contact
- Fomites
-
What are long term complications of chlamydia trachomatis infection
- Pelvic Inflammatory disease in women --> infertility / atopic pregnancies
- Reactive arthritis = Reiter?s syndrome
-
What is the pathogenesis of Reiter?s syndrome?
- Maladaptive autoimmune response
- Antibodies against bacteria cross react and attack the body
-
What is the clinical presentation of Reiter?s syndrome?
- Can?t see, can?t pee, can?t climb a tree
- Reactive arthritis often in sacro-iliac joint / knee
- Uveitis = infection of the eyes
- Urethritis
-
What could cause Reiter?s syndrome
-
How do we treat chlamydia infection?
- Treatment is very effective
- Macrolides ? azithromycin
- Tetracycline ? Doxycycline
-
Why can?t we use penicillins to treat chlamydia infections?
Do muramic acid in their cell wall so antibiotics that target cell wall?s cannot be used
-
How do we treat neonatal conjunctivitis caused by chlamydia trachomatis D-K?
- Topical macrolides are not effective for conjunctivitis in the newborn
- Oral Macrolides must be given
-
Why do we use combination therapy to treat chlamydia trachomatis D-K STD?
- Treat for gonorrhea too
- Often have a coinfection with Neisseria gonorrhea
- Often hard to tell them apart as they present almost identically
-
How do we treat chlamydia trachomatis D-K STD?
- Combination therapy
- Macrolides ? azithromycin (chlamydia trachomatis D-K)
- Ceftriaxone (Neisseria gonorrhea)
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What does chlamydophila pneumoniae infection cause
Atypical pneumonia in adults
-
What is walking pneumonia
Atypical pneumonia
-
What bacteria cause atypical pneumonia
- Legionella pneumophila
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
-
Which bacteria more commonly causes atypical pneumonia in the elderly
Chlamydophila pneumoniae
-
How do we treat chlamydophila pneumoniae atypical pneumonia?
- Tetracycline ? doxycycline
- Macrolides ? azithromycin
-
What does Mycoplasma pneumoniae cause
Walking pneumonia = atypical pneumonia
-
What gram stain is mycoplasma
No gram stain
-
Why doesn?t mycoplasma stain with gram stain
No cell wall
-
What do mycoplasma have instead of a cell wall
Special cell membrane with cholesterol in it
-
What is the function of cholesterol in mycoplasma cell membrane?
- Stabilize membrane
- Allow membrane to be more flexible
-
What is the only bacteria with cholesterol in their cell membrane?
Mycoplasma
-
What is the molecular structure of a sterol?
4 ringed structure made of benzene rings
-
What bacteria cause atypical pneumonia
- Legionella pneumophila
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
-
Why do we call atypical pneumonia this way?
Can?t easily culture or isolate the microbes causing it
-
Why do we call atypical pneumonia caused by Mycoplasma pneumoniae a walking pneumonia?
Severe pneumonia seen on X-ray but not too many clinical symptoms
-
What is the clinical presentation of walking pneumonia caused by Mycoplasma pneumoniae?
- Few clinical symptoms
- X-ray appears much worse than patients do clinically
-
What does an X-ray for Mycoplasma pneumoniae atypical pneumonia look like?
Reticulo nodular / patchy infiltrate
-
Who is most affected by Mycoplasma pneumoniae infection
Young adults in areas of close contact (e.g. Military)
-
How do you diagnose Mycoplasma pneumoniae infection?
Cold agglutinins found in 50-70% patients
-
How do we grow Mycoplasma pneumoniae?
- Takes a week
- Eaton?s agar
-
What are cold agglutinins
- 1-2 weeks into Mycoplasma infection people develop IgM molecules that agglutinate erythrocytes in cold temperatures
- Can lead to lysis of red blood cells
-
What is the molecular structure of IgM?
Pentamere circles
-
How do we treat Mycoplasma pneumoniae infection?
Macrolides ? erythromycin
-
Why can?t we use penicillins to treat mycoplasma pneumoniae infection?
No cell wall so cannot use antibiotics that target cell wall
- What does Enterobacter cloacae infection cause?
- Pneumonia
- Urinary Tract Infection (UTI)
-
Where do we find Enterobacter cloacae?
In hospitals ? nosocomial infections
-
Why is Enterobacter cloacae a nosocomial infection?
Multidrug resistance
-
How do we treat Enterobacter cloacae infection?
Carbopenems ? no resistance
-
why are there nosocomial infections
multidrug resistance
-
how do we treat nosocomial infections?
Carbopenems ? no resistance
-
what are Enterobacter cloacae biochemical properties?
ferment lactose
-
which Enterobacteriaceae ferment lactose
- Enterobacter
- Serratia
- Klebsiella
- E. coli
-
How do we detect lactose fermenters?
Form pink colonies on MacConkey agar
-
What gram stain is Enterobacter cloacae
Gram ? rod (Enterobacteriaceae)
-
What are Enterobacter cloacae virulence factors?
Motile
-
What does serratia marcescens infection cause
- Pneumonia
- Urinary Tract Infection (UTI)
-
Where do we find serratia marcescens?
In hospitals ? nosocomial infections
-
Why is serratia marcescens a nosocomial infection
Multidrug resistance
-
How do we treat serratia marcescens infection?
Carbopenems ? no resistance
-
what are serratia marcescens biochemical properties
ferment lactose (very slowly)
-
what gram stain is serratia marcescens
gram ? rod (Enterobacteriaceae)
-
what are serratia marcescens virulence factors
motile
-
how do we differentiate serratia from other Enterobacteriaceae?
produces red pigment when cultured
-
where can you find serratia bacteria
anywhere ? e.g. pink ring when don?t clean shower is serratia
-
What does klebsiella pneumoniae infection cause
- Pneumonia
- Urinary Tract Infection (UTI)
-
Where do we find klebsiella pneumoniae?
In hospitals ? nosocomial infections
-
Why is klebsiella pneumoniae a nosocomial infection
Multidrug resistance
-
How do we treat klebsiella pneumoniae infection?
Carbopenems ? no resistance
-
what are klebsiella pneumoniae biochemical properties
- ferment lactose
- urease positive
-
what gram stain is klebsiella pneumoniae
gram ? rod (Enterobacteriaceae)
-
who does klebsiella pneumoniae affect
alcoholics ? due to aspiration
-
how do klebsiella pneumoniae pass into the lungs
aspiration
-
how does klebsiella pneumoniae infection present
- abscesses ? cavitary lesions that resemble TB
- current jelly sputum
-
what are the virulence factors of klebsiella pneumoniae?
- polysaccharide capsule
- NON motile
-
what is the capsule of klebsiella pneumoniae mad of?
polysaccharide
- What species are in the proteus genus
- Proteus mirabilis
-
What gram stain are proteus
Gram ? rod (enterobactericiae)
-
What does proteus look like when plated
- Demonstrates swarming motility
- Fishy odor
-
What are virulence factors of proteus?
Motility
-
What kind of motility does proteus have?
Swarming motility when plated
-
What shape do kidney stones formed in the renal pelvis due to proteus have?
Stag horn calculi
-
What do proteus infections cause
- Stag horn calculi of the renal pelvis
- Urinary Tract Infections (UTI)
-
What are biochemical properties of proteus
Urease +
-
What is important for proteus to be able to form stag horn calculi
Urease
-
What is the function of urease?
- Produces ammonia and CO2 rom urea
- Creates alkaline environment
-
How does proteus cause stag horn calculi
- Creates alkaline environment (urease)
- Perfect environment for precipitation of struvite stones
-
What are struvite stones made of?
- Ammonia
- Magnesium
- Phosphate
-
What is the complication of struvite kidney stones?
- Pain
- Kidney damage
- Nidus for proteus --> recurrent infections
-
How do you treat proteus infection?
Sulfonamides
-
Who is the founding father of microbiology?
Louis Pasteur
-
Where can we find Pasteurella multocida
Respiratory tract of small mammals ? cats / dogs
-
How is Pasteurella multocida transmitted to humans
Dogs and cat bites
-
What does Pasteurella multocida infection cause
- Soft tissue infections --> Cellulitis in first 24 hours --> necrotizing fasciitis / osteomyelitis
- Lymphadenopathy
- Systemic infection
-
What is the clinical presentation of Pasteurella multocida infection?
Erythematous area of skin where bite is
-
How long after initial exposure does Pasteurella multocida cause infection
Within first 24 hours
-
Who is at most risk for systemic spread of Pasteurella multocida
- Liver disease patients
- COPD patients
-
What biochemical properties does Pasteurella multocida have?
-
What are Pasteurella multocida virulence factors
Capsule
-
How do we grow Pasteurella multocida?
5% sheep?s blood agar
-
What gram stain is Pasteurella multocida
- Gram ? coccobacillus
- Bipolar staining = safety pin staining
-
What is bipolar staining
- Bacteria takes up stain most readily at its 2 ends
- Looks like safety pin
-
Which bacteria demonstrate bipolar staining
- Pasteurella multocida
- Yersinia enterocolitica
-
How do we treat Pasteurella multocida infection?
- Penicillin ? amoxicillin
- AND Beta lactamase inhibitor (prevent resistance) ? clavulanic acid
-
Why do we use combination of penicillin and beta lactamase inhibitor in treatment of Pasteurella multocida?
To prevent development of resistance
-
What does chlamydophila psittaci cause
Pneumonia
-
How is chlamydophila psittaci transmitted
Birds ? often parrots
-
What does Gardnerella vaginalis cause
bacterial vaginosis
-
what is the clinical presentation of bacterial vaginosis caused by Gardnerella vaginalis?
thin greyish white malodorous (fishy) discharge from vagina
-
what gram stain is Gardnerella vaginalis
- Gram variable rod
- Stains as either gram + or gram -
-
How does Gardnerella vaginalis cause infection
- Increase in anaerobic flora of the vagina --> overgrowth --> decreased amount of lactobacilli
- Creates environment more suitable for Gardnerella vaginalis
-
What is the normal vaginal flora?
- Mainly Lactobacilli
- Minority of anaerobic gram ?
-
How do we diagnose vaginosis caused by Gardnerella vaginalis?
- Discharge should have a pH above 4.5 (usually between 5 ? 6.5)
- Whiff test
- Microscopic exam ? with wet mount
-
What is the whiff test?
- Prep vaginosis discharge with 10% KOH and smell pungent fishy odor
- Diagnosis for Gardnerella vaginalis vaginosis
-
How do we do a microscopic exam of Gardnerella vaginalis
- Wet mount preparation of bacterial vaginosis discharge
- Clue cells
-
What are clue cells
Epithelial cells diffusely coated with Gardnerella vaginalis bacteria
-
How do we treat bacterial vaginosis caused by Gardnerella vaginalis?
Metronidazole
-
Which bacteria do we treat using metronidazole
- Clostridium difficile
- Gardnerella vaginalis
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