-
staphylococcus structural molecules
- capsule
- protein A
- polysaccharide A
- bound coagulase
-
staphylococcus extra-cellular enzymes
- coagulase
- tissue destruction
- -hyaluronidase
- -staphylokinase
- -lipase
- beta-lactamas
- -penicillinase
-
MRSA stands for
Methicillin-Resistant S. aureus
-
MRSA facts
- subgroup (~40%) of S. aureus that is resistant to drugs including penicillin
- accounts for majority of infections
- flesh eating
-
MRSA death rate
a patient with a hospital acquired infection is about 7 times more likely to die than an uninfected patient
-
MRSA treated with...
- vancomycin
- but signs that these strains are now developing a resistance
-
Hemolysins
- (endo)toxin in staphylococcus
- broken down into alpha, beta, gamma, and sigma Sphingomylinease C
- lyse RBC
- know that there are many types
-
Leukocidin
- (endo)toxin of staphylococcus
- lyse leukocytes
-
Exfoliatin
- (endo)toxin of staphylococcus
- deals with skin
-
enterotoxins
- toxins of staphylococcus
- causes gut problems
-
TSST-1
- Toxic Shock Syndrome Toxin-1
- toxin of staphylococcus
- super antigen
- causes T cells to be released, but they do nothing besides cause fever
-
TSST-1 structure
- TCR alpha chain
- TCR beta chain
- MHC II alpha chain
- MHC II beta chain
- TSST
- antigen peptide in middle
-
skin infections from staphylococcus
- direct tissue invasion
- boils (furuncles)
- carbuncles
-
organ infection from staphylococcus
- direct organ invasion
- pneumonia
- meningitis
- acute endocarditis
- others
-
exotoxin release of staphylococcus
- scaled skin syndrome
- gastroenteritis
- toxic-shock syndrome
-
skin infection of staphylococcus steps
- invasion
- inflammation
- suppuration (pus formation)
- abscess formation in sebaceous gland
-
scaled skin syndrome
- from staphylococcus
- bullous impetigo
- Ritter's disease
-
Gastroenteritis
- caused by enterotoxins
- food poisoning
- infection
- vomiting
- diarrhea
- abdominal pain
- nausea
-
Toxic Shock syndrome symptoms
- caused by TSST-1 superantigen
- fever
- septic shock
- diffuse erythematous rash
- desquamation of palms and soles
- vomiting and diarrhea
-
Treatment of staphylococcus
- Antibiotics
- drainage
- vaccine
-
antibiotics used on staphylococcus
-
vaccines used on staphyloccus
- capsular polysaccharide
- RAP (RNA activating protein)
-
prevention of staphylococcus
- breaks in skin or mucous membrane
- clean wounds with iodine or hexachlorophene
-
sources of staphylococcus
- shedding human lesion
- material contaminated
- skin/respiratory tract secretions
-
how to minimize staphylococcus
- hand washing
- sterilization of instruments
- covering exposed skin area
- exclude personnel with active S.aureus lesion
-
-
staphylococci features
- gram positive
- non motile
- non-spore forming
- pyogenic
- normal flora
- catalase positive
- facultative
-
streptococci features
- gram positive
- non-motile
- non-spore forming
- pyogenic
- normal flora
- **catalase negative
- facultative or resistant
-
streptococcus hemolytic type
- **alpha hemolytic (semi)
- **beta hemolytic (complete)
- gamma none-hyemolytic
-
streptococcus serologic type group specific
- C carbohydrate
- Lancefield group
- A,B,D,....V
-
streptococcus serologic type; type specific
- capsule polysaccharides
- cell wall with protein M, T, and R
-
Beta hemolytic streptococci
- cause most streptococci infections
- most virulent in group A
-
Protein M in streptococcus
with Group A strep are virulent
-
S. pyoogenes
- Group A (GAS)
- streptococcus
- has M protein, so resistant to phagocytosis
-
GAS enzymes
- streptokinase (fibrinolysin)
- deoxyribonuclease (DNase)
- Hyaluronidase
-
GAS proteins
- **Pyrogenic exotoxins (erythrogenic toxins)
- Streptolysins (O-oxygen labile and S-oxygen Stable)
-
S. mutans
causes dental caries
-
M protein
- resistant to phagocytosis
- inhibits binding of C3b to bacterial cell surface
- alpha helical structure
-
Streptococcus group A pathogenesis
- Infection is localized and invasive
- likes to live in the skin
- toxin related
- **post-infectious autoimmune diseases
-
Group A localized infections
- strepococcal pharyngitis
- scarlet fever
- streptococcal impetigo (pyoderma)
-
streptococcal pharyngitis
- strep throat
- Beta-hemo
- produces pyrogenic toxin that causes scarlet fever
-
Streptococcus invasive diseases
- erysipelas
- necrotizing fasciitis (streptococcal gangrene
-
S.pyogenes
- "flesh-eating bacteria"
- causes necrotizing fasciitis
-
streptococcus toxin release
- streptococcal toxin shock syndrome
- M protein
- pyrogenic toxins
-
streptococcus post-infection autoimmunity
- rheumatic fever
- acute glomerulonephritis
- strep throat
-
streptococcus treatment
- antibiotic
- -penicillin G,V
- -erythromycin
- -penicillinase resistant penicillin
- or vaccine
-
streptococcus pneumoniae
- aka pneumococci
- alpha hemolytic
- gram (+)
- diplococci
- facultative
- throat and nasopharynx flora
-
most common cause of bacterial pneumonia and meningitis
- streptococcus pneumoniae
- aka pneumococci
-
streptococcus pneumoniae virulent factors
- **polysaccharide capsule
- IgA protease
- pneumolysin
-
Streptococcus pneumoniae typing
- based on capsular polysaccharide
- **Quelling (swelling)reaction or capsule test
-
pathogenesis of pneumonia
- Viral infection or impaired mucus drainage
- causes epithelial damage
- causes S.pneumoniae invasion
-
S. pneumoniae clinical manifestation
- abrupt onset
- chills and very high fever
- chest pain
- blood-tinged sputum
- post viral infection
-
S. pneumoniae treatment/control
- Penicillin G
- erythromycin
- ceftriaxone
- vaccine (23 types)
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