Gram Positive Cocci Flashcards
How many colony forming units per ml indicates bacterial pneumonia in BAL specimens?
> 10^4 CFU/mL = 10,000
Staph AUREUS is susceptible to ______ (bacitracin (A) / furazolidone (FX)) and resistant to (bacitracin(A) / furazolidone (FX))
susceptible to furazolidone; resistant to bacitracin
Micrococcus is susceptible to ______ (bacitracin (A) / furazolidone (FX)) and resistant to (bacitracin(A) / furazolidone (FX))
Susceptible= bacitracin Resistant= furazolidone
Where does SAUR naturally colonize?
Nares, skin folds, perineum, axillae, vagina
What organism cause pyoderma, folliculitis, impetigo, furuncles, carbuncles, and post surgical wound infections?
SAUR
What are THREE toxin-mediated infections caused by SAUR?
Scalded scalp syndrome, toxic shock syndrome, and food poisioning
What organism causes scalded scalp syndrome in neos?
SAUR
What are SAUR virulence factors that interfere with phagocytosis? (4)
Capsules, Protein A, Panton-Valentine Leukocidin (PVL), and coagulase
SAUR can cause food poisoning in how many hours after ingesting enterotoxin?
2-8 hours
Name three enzymes that SAUR possesses as virulence factors
Fibrinolysins, hyaluronidase, and phospholipase C
What type of coagulase is known as “bound coagulase” or “clumping factor”?
Slide coagulase
What type of coagulase (slide or tube) reacts directly with fibrinogen in plasma causing rapid cell agglutination?
Slide
What coagulase negative staph species produce clumping factor and may be positive with slide coagulase?
Staph lugdunensis and S. schleiferi
What is the next step if the slide coagulase test is negative?
Perform tube coagulase
What type of coagulase is associated with TUBE coagulase? (Bound or free)
Free coagulase
What type of coagulase (Bound/Free) reacts with substance in plasma called caogulase-reacting factor that converts fibrinogen to fibrin?
Free - tube coagulase
If a tube coagulase test is negative after 4 hours incubated at 35C, what is the next step?
Held at room temperature and read again after 18-24 hours
RARE: some SCNE isolates such as S. intermedius, S. hyicus, S. delphini, S. schleiferi may be _____ (slide/tube) coagulase positive
Tube
What organism is resistant to LysoStaphin?
Micrococcus
Staph lugdunensis and Staph schleiferi may produce clumping factor and be positive with what test?
Latex Agglutination test
What organism is associated with indwelling urinary catheters and hospital acquired UTIs
Staph epi
What organism is associated with infections of indwelling devices
SEPI
What coagulase negative staph species is associated with acute UTIs & is the second most common cause of UTIs after ECOL
Staph saprophyticus
Staph saprophyticus is _____ (sensitive/resistant) to Novobiocin (NV)
Resistant
Staph lugdunensis is positive to what two biochemical rxns?
PYR and ORNITHINE (+)
What species is a GPC that forms grey to white, mucoid colonies on BAP, and has a tendency to adhere to agar – when removed will form a string?
Rothia mucilaginosus
What is the transmission of healthcare associated MRSA (HA-MRSA)
Hand contact
MRSA infections that are acquired by individuals who have not been recently hospitalized or had an invasive medical procedure are known as what type of MRSA infections?
CA-MRSA
Coagulase negative staph species are susceptible to ______ (bacitracin (A) / furazolidone (FX)) and resistant to (bacitracin (A) / furazolidone (FX))
Resistant to bacitracin
Sensitive to furazolidone
What gene encodes for altered penicillin-binding protein 2a (PBP2a)
MecA
MecA is carried on a mobile genetic element called what?
Staphylococcal cassette chromosome mec – (SCCmec)
What MRSA is more susceptible to antibiotics? (HA or CA)
CA-MRSA
BBL CHROMAgar MRSA contains what antibiotic to screen for MRSA?
Cefoxitin