staphylococci

are staphylococci aerobes or anaerobes?

aerobes and facultative anaerobes

what is the only coagulase positive staph?

staph aureus

what is coagulase?

enzyme that converts fibrinogen to fibrin (clot)

what are the infections associated with staph aureus?

number 1 cause of:

- otitis externa

- osteomyelitis

- septic arthritis

- acute infective endocarditis

also causes:

- skin infections

- HAP/severe pneumonia

- meningitis

- brain abscess

which skin infections are cause by staph aureus?

- impetigo

- cellulitis

- local abscess

what does staph aureus produce?

exotoxins

what are the disease caused by staph aureus exotoxins?

- gastroenteritis

- toxic shock syndrome

- staphylococcus scalded skin syndrome (SSSS)

what are the features of gastroenteritis infection?

- exotoxin builds up in food e.g. finger food/mayonaise

- diarrhoea, vomiting and abdo pain

- rapid onset and rapid recovery (within 24hrs)

what are the features of toxic shock syndrome?

- after childbirth/abortion/prolonged tampon use

- diffuse red rash, fever, disulpharimation of palms and soles

what are the features of scalded skin syndrome?

- often children/neonates

- peeling skin

what are the different types of resistances within staph bacteria?

- methicillin-susceptible

- methicillin-resistant

- vancomycin resistant

what is the mechanism of resistance of methicillin-resistant bacteria?

PBP-mediated resistance (penicillin-binding protein mutate)

- decreases the affinity for penicillin to bind

what is the mechanism of resistance of vancomycin-resistant bacteria?

peptidoglycan synthesis alteration

what is the first choice of antibiotics for methicillin-susceptible staph aureus?

cephalosporins

what are the choices of antibiotics for MRSA?

- vancomycin

- teicoplanin

- linezolid

what are the choices of antibiotics for VRSA?

- linezolid

- daptomycin