Streptococci/Enterococci Overview Flashcards
Streptococcus spp gram stain
Oval GPC in pairs and chains
Streptococcus spp key characteristics
Catalase neg. Facultative anaerobes. Require enriched media. Chaining best in broth cultures.
Group A streptococci (GAS) gram stain
Oval GPC in chains
Group A streptococci (GAS) key characteristics
Sensitive to bacitracin. Resistant to SXT. PYR pos. Most common is S. pyogenes.
Group A streptococci (GAS) pathogenicity
Causes 90% of strep infections. Strep sore throat, rheumatic fever, glomerulonephritis, scarlet fever (scar- latina), erysipelas, puerperal sepsis, impetigo
Group B streptococci (GBS) gram stain
Oval GPC in chains
Group B streptococci (GBS) pathogenicity
Normal flora of fe- male genital tract. Most common cause of neonatal septicemia & meningitis
Group B streptococci (GBS) key characteristics
Resistant to SXT & bacitracin. Sodium hippurate pos. CAMP pos.
Group D streptococci, nonenterococci gram stain
Oval GPC in chains
Group D streptococci, nonenterococci pathogenicity
Normal in GI tract. Causes nosocomial UTI, wound infections, bacteremia
Group D streptococci, nonenterococci key characteristics
Hydrolyzes esculin
Enterococcus gram stain
Oval GPC in pairs & chains
Enterococcus pathogenicity
Normal in mouth, GI tract, female genital tract. Causes nosocomial UTI, wound infections, bacteremia
Enterococcus key characteristics
Hydrolyzes esculin. Grows in 6.5% NaCl broth. PYR pos
Streptococcus pneumoniae gram stain
(lancet-shaped) GPC. Usually in pairs
Streptococcus pneumoniae pathogenicity
Most common cause
of community-acquired pneumonia. Major cause of otitis media, meningitis in adults. Infects sinuses, eyes
Streptococcus pneumoniae key characteristics
Bile solubility pos. Sensitive to optochin
Viridans streptococci gram stain
GPC in chains
Viridans streptococci pathogenicity
Frequent cause of subacute bacterial endocarditis. Gingivitis & dental caries (cavities)
Viridans streptococci key characteristics
Resistant to optochin. Bile solubility neg
