Staphylococcus aureus Flashcards
what are the growth characteristics of S. aureus?
not fastidious
facultative anaerobe
coagulase positive
catalase positive
-usually extracellular, but can be facultative intracellular
what are the key virulence factors of S. aureus?
coagulase positive
PVL associated w/ MRSA
teichoic acid=endotoxin like shock
what specific type of infx is S. aureus most common cause of in the US?
skin and soft tissue infx
what general type of infx is S. aureus most common cause of in US hospitals?
invasive infx
what is the key mode of transmission of S. aureus?
fomites (counter, sheets, counter tops, etc)
what is the reservoir for S. aureus?
can be animals, but usually humans
what is the key risk factor for S. aureus?
catheters, IVDU
-pretty much anything hematogenous
what type (CAP, HAP, HCA-P) of pneumonia does S. aureus usually cause?
HAP
Is S. aureus an opportunistic or frank pathogen?
opportunistic
-although it is NMF, usually acquired exogenously
what is a major complication (secondary infx) associated with S. aureus infx?
Acute Infectious Endocarditis
-2 positive S. aureus blood cultures
what is MSSA resistant to?
penicillin
what causes penicillin resistance in MSSA?
B-lactamase production
what is used to treat MSSA infx?
oxacillin
nafcillin
(used to be methicillin)
what causes methicillin resistance in MRSA?
altered target site via mutation (PBP)
NOT B-lactamase production
what is used to treat MRSA?
vancomycin
