Gram positive pathogens Flashcards
Staphylococci are all ________ positive
catalase positive
S. aureus is________ positive
coagulase
S. aureus think:
Think: abscesses, toxins, septic shock, drug resistance
S. aureus is a highly successful _________pathogen.
opportunistic
S. aureus is __________hemolytic.
S. aureus are β-hemolytic
_________ is an enzyme that is bound to the S. aureus surface and also secreted into the environment. It binds to and activates prothrombin, which converts fibrinogen to fibrin on the bacterial surface. Mixing isolates with plasma causes major clumping of the colonies and clotted fibrin.
Coagulase
So, coagulase is also called____________
clumping factor.
what is the significance of small colony variants of S. aureus?
These are tiny colonies on blood agar plates compared to most staph and they may require prolonged incubation to even see them. . SCVs are usually recovered from protracted, difficult-to-treat infections, such as chronic osteomyelitis or infected prostheses. They are also described in S. aureus infections of patients with cystic fibrosis.
what are some of the molecular diagnostics used to identify staph infections?
Flourescent 16S rRNA, Multi-plex real-time PCR, pulse file gel electrophoresis, multilocus sequence typing, Spa and Spa/ClfB typing
what is MSCRAMM?
microbial surface component reacting with adherence matrix molecules
Coagulase Negative staphylococci think:
Think: indwelling medical device, biofilms, indolent infections, drug resistance.
________is now the most common cause of primary bacteremia.
S. epidermidis
_______grows mainly in the GI and GU tracts.
S. saprophyticus
the three stages of biofilm formation:
adhesion, maturation, and dispersal
Poly-gamma-DL-glutamic acid (PGA). S. epi and other CoagNS make PGA but not ____________ It acts as an antiphagocytic capsular material, and also facilitates colonization of and persistence on skin.
S. aureus
