staph- daniels Flashcards
staphylococcus characteristics
gram positive cocci
non-motile
non spore forming
predominantly facultative anaerobes
differentiates s. aureus and 6 other species from among 42 total species
coagulase test
___ causes the highest burden of disease in people
s. aureus
s. aureus lives on and around ____ with 30-40% prevalence of _____
people; nasal carriage
s. aureus found at _____ and ____ surfaces
mucocutaneous junctions; skin, mucosal
multiplication/ spread of s. aureus is variable with:
- bacterial inoculum (more is worse)
- host immunocompetence
- location of infection
MSCRAMMs
microbial surface components recognizing adhesive matrix molecules
____ is a key player in the ECM function of adhesion
fibronectin (fibronectin binding proteins)
collagen binding protein binds:
cartilage, connective tissue, bones, joints
clumping factors bind ____
fibrinogen
functions of fibrinogen
- important in clot formation
- responsible for positive coagulase test in vitro
- key in pathogenesis of endocarditis
damage of s. aureus
acute suppurative inflammation (i.e. accumulation of pus)
pus is essentially…
neutrophils or polymorphonuclear WBCs (aka PMNs)
neutrophils release toxic oxidative substances to try to kill bacteria, called _____
reactive oxygen species (ROS)
ROS payload also damages host tissue due to _____
sustained inflammation
virulence factors of s. aureus
- polysaccharide capsule
- protein A
- pore-forming toxins (including Panton-Valentine Leukocidin)
toxins cause the layers of the epidermis to separate
staphylococcal scalded skin syndrome (SSSS); exfoliative toxins A and B
exfoliative toxins are ____ with high specificity for _____ in the skin
proteases; desmosomal proteins
TSST-1 is a ____ that causes _____
superantigen; toxic shock syndrome
superantigens cause an unregulated inflammatory response by activating high levels of _____
CD4+ T cells
in toxic shock syndrome, cytokine storm initiated by CD4+ cells causes:
IL1 –> fever
TNFalpha and beta –> hypotension and capillary leakage
IFNgamma, IL2 –> rash
in staphylococcal food poisoning, many strains of s. aureus secrete ____
enterotoxins (ABCD and E)
_____ cause intense peristalsis
superantigens
____ and _____ or ____ make the crosslinks in peptidoglycan
transpeptidases; transglycosylases; Penicillin Binding Proteins
____ are inhibitory substrates for penicillin binding proteins (PBPs)
beta-lactam antimicrobial agents
examples of beta-lactam antibiotics (which inhibit cell wall synthesis of bacteria)
penicillins semi-synthetic penicillins -cephalosporins -carbapenems -monobactams
2 types of penicillin binding proteins of s. aureus
methicillin susceptible staph aureus (MSSA)
methicillin resistant staph aureus (MRSA)
____ is frequently used to treat MRSA or presumed MRSA
vancomycin
vancomycin is a ____ class antimicrobial drug
glycopeptide
