ID Exam 1

Single stranded vs double stranded and enveloped vs non enveloped

• Herpes simplex virus type 1
• Herpes simples virus type 2
• Varicella Zoster virus
• epstein barr virus
• cytomegalovirus
• Hepatitis B

• Single vs double stranded
• For singled stranded positive vs. negative
• Non-enveloped vs enveloped

staphylococcus aureus

Staphylococcus epidermidis and staphylococcus saprophyticus

• Enterococcus spp., alpha hemolytic strptococci,
• and beta Hemolytic streptococci

• Bacillus spp.
• coynebacterium spp.,
• gardnerella barinalis,
• actinomyces spp.,
• lactovavacillus acidophilus,
• listeria monocytogenes,
• nocardia spp.
• rhodococcus equi

enterocacteriaceae

• Escherichia coli
• Klebsiella spp.
• Enterobacter spp.
• Serratia marcescens
• Citrobacter spp.

• Proteus spp.
• Providencia stuartii
• mroganella morganii
• Salmonella spp.
• Shigella spp.

• Enterobacteriaceae
• aeromonas hyprophila
• Vibrio Cholerae
• Pasterella multocida

• Pseudomonas aeruginosa
• Acinetobacter spp.

• Haemophilus spp
• campylobacter jejuni
• Legionella pneumophilia

• Moraxella catarrhalis
• Neisseria spp.

• Clostridium spp.
• peptostreptococcus spp.
• Propionibacterium acnes

• Bacteroides fragilis
• Prevotella spp. 
• Fusobacterium spp.

• Chlamydia spp.
• Mycoplasma spp.
• Legionella spp.

the lowest concentration of an agent that inhibits the visible growth of an organism

The lowest concentration of an agent that results in a 99.9% reduction in colony forming units.

• Macro-broth dilution
• micro-broth dilution
• agar dilution
• kirby bauer disk diffusion
• Epsilometer strip
• automated system

• system developed to aid clinicians evaluate MIC results.
• Breakpoint value is based on:
• drug pharmacokinetics and pharmacodynamics
• distribution of MICS of a population of bacteria
• clinical efficacy

summarize of bacteria suscepatibleity to antibiotics

• Do not provide regarding the rate or extent of bactericidal activity
• MIC are conducted with a standard incoulum
• Media does not contain plasma proteins or complement

Following a dose blood is obtained and serially diluted. Bacteria are added to the serum and the inhibitory and bactericidal titers recorded.

the largest dilution of a sample that inhibits the visible growth of an organism

the largest dilution of a sample that results in a 99.9% reduction in colony forming units.

• Larger dilutions contain less drug
• SIT and SBT take individual pharmcokinetics into account
• Can be used to evaluate antimicrobial therapy

• provide data regarding the dynamics of antimicrobial activity
• broth is inoculated with a test isolate at a standard inocula and a known amount of antibiotic 
• Samples are removed from testing containers at predetermined time points and plated on agar

• overuse of broad-spectrum agents
• used for the treatment of non-bacterial infections
• inappropriate antimicrobial prophylaxis

• Failure to complete antimicrobial regimens
• non-compliance
• patient self-medication

• Nearly 1/2 of the antibiotic usage is in farm animals
• increasing reliance on aquaculture

• Naturally occurring 
• Prior antimicrobial exposure is not required
• predictable
• also refereed to as inherent, intrinsic , or native resistance

• develops following antimicrobial exposure
• Not predictable
• Also referred to as acquired resistance

• a bacterial population is comprised of isolated with varying MIC
• Isolates with low MIC are easily killed
• Resistant subpopulations remian grow

• Spontaneous mutiations
• acquisition of new genetic material

• Patient education 
• knowledge of local susceptibility patterns
• prescriber education
• develop guidelines for appropriate antimicrobial usage
• vaccination 
• Hand washing

• rubella 
• west nile 
• Hepatitis C
• HIV

• Influenza virus
• Respiratory syncytial virus (RSV)
• Mumps
• measles
• rabies
• ebola
• haunta

• Either DNA or RNA-NOT BOTH
• Single stranded ss or double stranded DS
• sommonly ds DNA or ss Rna

the positive stand can be used directly as a template for protein synthesis while the negative strand cannot.

• Protein shell
• helical-rod shaped or coiled
• icosahedral-symmetrical
• complex-not helical or icosaherdral

• 1. Viral adsorption/attachment
• 2. viral penetration
• 3. Viral uncoating
• 4. replication of the viral genomes and other viral components
• 5. self-assembly of progeny viruses (viral replication)
• 6. Release of progeny viruses

• attachment of virus to a host cell
• viral attachment structures
• cell surface proteins often hijacked by viruses

passage of the complete virus from the target cell surface into the cytoplasm through the membrane

• disassembly of the complete virus
• depend on enzymes from the infected cells

• No progeny virus is produced
• the virus enters a cell that lack necessary machineries for replication
• a defective virus 
• Cell death due to viral infection

viral genome is within the infected cell, but no progeny is produced until viral reactivation

The infected host cell lives and continues to divide and function

the infected host cell dies because its normal macromolecule metabolism is impaired the infecting virus aims to maximize viral replication.

• Influenza A & B
• Respiratory synacial virus

Parainfluenza 1,3,4

• West Nile Virus
• enterovirus

Rotavirus

• Parainfluenza 3
• Noravirus
• Adenovirus
• Herpes Simplex 
• Varicella zoster
• Cytomeglovirus
• HIV

• Replicate within the nucleus
• The envelop contains antigenix glycoproteins that are species and tissue specific
• Following primary infection, all herpes virus can enter into the latent phase and be activated at a later time throughout life

• Herpes simplex virus 1
• Herpes Simplex Virus 2
• Varicella Zoster Virus HHV-3

• Cytomegalovirus HHV-5
• Human herpes virus 6

• Epstein Barr Virus HHV4
• Human herpes virus 8

oropharyngeal and labiofacial surfaces, other sites

Genital squamous surfaces

• Saliva to oropharyngeal and labiofacial surfaces
• Some cases of skin-to-skin transmission

Intimate sexual contact

cutaneous herpes lesions that heal without scarring

Migrate through the sensory nerves fibers to the trigemental gangion and persists indefinitely in a dormant state

• Migrate to the sacral neural ganglia. 
• Reactivation rates are at least twice as high with HHV 1

• Reactivate of HHV is only a problem for immunocompromised patients
• Encephalitis and meningits are the main problems

• Prutic vesicles progresses to ulcers, crust over and heal without scarring
• mild symptoms and minimal sequalae
• Virons travel by nerve fivers to regional sensory neural ganglions

• Reactivation of primary infection
• Spreads from trigeminal or dorsal root ganglia back down nerve fibers to the skin producing painful cutaneous vesicles with a classic dermatome distribution
• Can be very painful

• ds non-enveloped DNA virus
• over 70+ strands
• Induce hyperplastic epithelial lesion and malinancies
• Most HPV warts of the hands and feet are transient and has no medical consequence

• Anogenital wart: HPV 6 HPV 11
• Carcinoma: HPV 16 HPV 18
• Oral Cancer: HPV 13 and HPV 32

Kaposi sarcoma in severely immunocompromised patients. Specifically AIDs

• Widespread rash usually in children
• Caused by viruses that spread hematogenously to skin and mucous membranes

• Transmitted by direct contact with nose and throat discharge, saliva, fluid from blisters, or the stools of an infected person
• most contagious during the first week; 3-7 days before system appear
• transmission by inhalation or ingestion

• Herpangina
• myocarditis
• myostit
• pericarditis

• A high fever followed by a rash on neck trunk and thigh commonly seen in infants
• transmission from saliva possible

• ssRNA - enveloped viruses
• transmission by sneezing/coughing droptlets
• extremely infectious
• Replicate in respiratory epithelial cells, then in lymphoid organce

• Rash
• fever
• upper respiratory tract symptoms
• conjuncitivitis
• Initial infection probably occurred 1-2 weeks prior
• Once the rash appears the patient is not infectious

• ssRNA + enveloped viruses
• Respiratory transmitted
• Commonly called german measles

significant damages to fetus due to necrosis in fetus

• One of the most deadly viral infections in human history
• Large ds DNA virus with complex genome
• Caused by either of two virus variants
• variola major and minor
• No specific treatment the only prevention is vaccination
• potentials as biologic weapon

• direct and fairly prolonged face-to-face contact
• direct contact with infected bodily fluids or contaminated objects such as bedding or clothing
• respiratory-uncommon

• Incubation 1-2 weeks, asymptomatic, not contagious
• Early symptoms, 3-4 days, high fever, malaise, head and body aches, and sometimes vomiting, may be contagious
• Rash and pustules, 1-2 weeks very contagious
• Resolution, 1 week contagious

• common cold
• acid labile

• common cold 
• GI infection

• common cold
• GI infections

• Influenza
• pneumonia

• common cold
• pneumonia
• croup in young children

Lower respiratory tract infections

Upper and lower respiratory tract infections.

• Severe acute respiratory syndrome
• Causes both upper and lower respiratory tract infections, muscle pain, fever
• Highly contagious; 10% mortality
• Originated from China & spread to N America

• Around winter months
• Causes most cases of watery diarrhea in infants and young children in the US
• Highly infectious 30%-50%
• Dehydration with electrolyte imbalance is the most serious complication

Clinically similar to rotavirus disease but has no seasonality

• affect children and adults-BUT NEVER INFANTS
• year round
• Can be non-enveloped can survive for days on inanimate surfaces
• acute gastroenteritis
• Oral fecal transmission

Cause nosocominal and day care center outbreaks

• ssRNA - enveloped viruses
• Transmission by respiratory droplets followed by viremia
• Usually affect children
• Acute febrile infection and swelling on the parotid gland in 2/3 patents

• Viral encephalitis 
• Deafness
• Male sterillity

• Uncommon in immunocompetent patients
• Usually occurs as a reactivation of latent HSV-1 that tracks into the cerebral cortex, producing a large necrotic mass
• Progression is rapid and mortality is high
• We have drug therapy for this

• ~75% of viral meningitis in the US 
• usually a relatively benign and transient disease in children and young adults
• coxsacki virus and echovirus
• spread easily from person to person via fecal oral means
• Often with annual summer-fall outbreaks

• Very uncommon in the US
• transmission by ingestion 
• necrosis of spinal cord or brainstem motor neurons
• Many asymptomatic but can cause flaccid paralysis

• This family mostly comes from insects
• Flavivirus
• togavirus
• bunyavirus
• West Nile virus

• simple fever to meningits, encephalitis, and flaccid poliomyelitis paralysis
• Long term encephalitic and paralytic disabilities
• many fatalities-mostly elderly and immunocompromised patients
• Detected by IgM and IgG in CSF or serum

• caused by Epstein Barr cirus
• spread by saliva and infect B cells
• primary infection in early childhood is usually asymptomatic 
• Classical occurs in the young adult years

• sore throat
• fever
• tonsillitis
• lymphadenopathy
• splenomegaly
• hepatitis
• fatigue
• malaise

• Nasopharyngeal carcinoma in Asians
• Burkitts lymphoma Africa

• Defined by clinical signs and symptoms rather than laboratory results
• Presistent fatigue accompanied by:
• fever
• pharyngitis
• tender lymphadenopathy
• athralgia
• myalgia

• Reactivation of latent EBV infection is linked to:
• B cell CNS Lymphoma in AIDS patients
• Post-transplant lympohoproliferative disorder (PTIF) in transplant patients

The most common opportunistic viral infection in HIV and transplant patients

• Pneumonia
• Hepatitis
• encephalitis
• esophagitis
• enterocolitis
• gastritis in HIV/AIDS patients
• Retinitis
• GI tissue damage 
• graft damage in transplant patients

JC virus and Bk virus

a rare fatal and demyelinating CNS disease

Refractory anemia and pansytopenia(low WBC, RBC, and platelets)

• transmission by direct animal/human bite sometimes by respiratory tract by infected bat dropping
• The virus replicate locally then move to the CNS through the peripheral neurons and then move to many organs through the autonomic nervous system
• Disease course 1-8 weeks latent in the beginning but highly variable
• Hallucinations, mental dysfunction, aggression, seizure, coma and death
• Once symptoms begin death is inevitable

Hemorrhagic fever high mortality

• Hemorrhagic fever 
• high mortality

• Hemorrhagic fever with or without renal syndrome and pulmonary syndrome 
• high mortality

• Produced by numerous gram+ and gram- microorganisms
• Inactivate beta lactam antibiotics by splitting the amide bond of the beta lactam ring
• Production of beta lactamases is either constitutive or inducible

• Enterobacter spp
• Citrobacter freundii
• Serratia marcescens
• Pseudomonas aeruginosa

• Cefotaxime 
• ceftriazidie
• imipenem
• Ceftazidime

• Active against all B-lactams except cephamycins, cefepime, and carbapenems
• Inhibited by B-lactamase inhibitors
• Most commonly found in K. pneumonia and E. coli
• Genes are located on plasmids

• Active against all B-lactams except cefepime and carbapenems
• not inhibited by b-lactamse inhibitors
•  Most commonly found in K. pneumonia, enterobacter spp, C. freundii, M. morgannii, S. marcescens, and P. aeruginosa
• Genes found on chromosomes and plasmids. Expression may be inducable

• Encoded for by the blaKPC gene
• Extensive cross resistance with other classes of antibiotics
• Only susceptible to colistin or tigecycline
• Expression is independently associated with increased mortality
• Standard susceptiblity testing may not identify KPC production
• Use a modified Hodge test

• Administer large doses of B-lactams to overwhelm the B-lactamases
• Combine b-lactams with b-lactamase inhibitors such as tazobactam, clavulanate, and sulbactam.

• Modification as the aminoglycoside is transported across the cell wall of the microorganism
• Commonly observed among enterococci exhibiting high lavel aminoglycoside resistance
• Chloramphenicol acetyltransferase
• erthromycin estrase

• 1. Penicillin-binding proteins (PBP)
• 2. ribosomal binding sites
• 3. Cell wall precursors
• 4. DNA gyrases

• Porin channels-Change in #
• Transport proteins
• Effllux Pumps-proteins that actively pump agent out of the bacteria

• Most resistance is secondary to expression of PBP that bind B-lactams with low affinity
• Staphylococcus are the only gram+ that produce B-lactamses
• staphylococci can also express an altered PBP2a.
• This is encoded for by the mec determinant found on the mobile staphylococcal chromosomal cassette mec elements

• Most reistance is seondary to the production of B-Lactamses
• developed in 4 waves:
• 1. emergence of narrow spectrum penicillinases
• 2. ESBL(resistance to extended spectrum cephalosporins, mainly K. pneumoniae
• 3. CTX-M
• 4.Carbapenemases

• High level resistance results from expression of operons that substitute a terminal d-lactate or d-serine for d-alanine
• Reduced vancomycin affinity
• Typically is only stable in the setting of continued vancomycin selective pressure

• Resistance reults secondary to accumulations of point mutations in topoisomerases
• In general single point mutations result in low-level resistance-Mutant prevention concentration

• Common nosocomial pathogen
• Isolation in the community is increasingly common especially among IVDU
• Resitance is secondary to the production of an altered PVP
• Resistance may be transferred via plasmids or transposons
• Multiple resistance to many common anti-staphylococcal agents is frequently encountered
• Treatment of choice is vancomycin

• VISA may be due to alterations in the cell wall and altered autolytic expression.
• TMP/SMX may be a treatment option for VISA

VRSA isolates possessed mecA and vanA genes. This suggests transfer of resistance determinants from enterococci

• S. pneumoniae is a common cause of a variety of community acquired infections including otits media, pneumonia, sinusitis, and pneumonia
• Overuse of antimicrobials in the community setting has overtime selected for resistant organisms
• The prevalence of penicillin-resistant isolates in the United states has risen
• The prevalence of penicllin resistance caries geographically and found more with people under the age of 6
• Pneumococcal resistance to penicillin is the result of expression of modified penicillin binding proteins
• Antimicrobial resistance in vitro does not necessarily translate into clincal resistance
• In the case of pneumonia even high level PCN resistance among pneumococci has not been clearly associated with PCN failure

• Increasingly common nosocomial pathogen
• Intrinsically resistant to numerous antimicrobials including cephalosporins and TMP/SMZ
• Monotherapy with penicillins or vancomycin are static
• Combination therapy with an aminoglycoside is necessary for a cidal effect
• acquired resistance to the penicillins is due to alterations is PBP
• High level aminoglycoside resistance is conferred by the production of amino glycoside modifying enzyems
• Isolation of vancomycin resistant strains is becoming increasingly problematic

• Van A: Inducible high level resistance to vancomycin and teicoplainin
• Van B: Inducible resistance to vancomycin susceptible to teicoplanin
• Van C: constitutive resistance to vancomycin may be susceptible to teicoplanin

• Vancomycin, linezolid, daptomycin. and streptogramins
• Intermittent vs. continusous infusions of b-lactams and vancomycin
• Tradition vs. once daily dosing of amino glycosides