Streptococci/Enterococci Overview

Question 1

Streptococcus spp gram stain

Answer 1

Oval GPC in pairs and chains

Question 2

Streptococcus spp key characteristics

Answer 2

Catalase neg. Facultative anaerobes. Require enriched media. Chaining best in broth cultures.

Question 3

Group A streptococci (GAS) gram stain

Answer 3

Oval GPC in chains

Question 4

Group A streptococci (GAS) key characteristics

Answer 4

Sensitive to bacitracin. Resistant to SXT. PYR pos. Most common is S. pyogenes.

Question 5

Group A streptococci (GAS) pathogenicity

Answer 5

Causes 90% of strep infections. Strep sore throat, rheumatic fever, glomerulonephritis, scarlet fever (scar- latina), erysipelas, puerperal sepsis, impetigo

Question 6

Group B streptococci (GBS) gram stain

Answer 6

Oval GPC in chains

Question 7

Group B streptococci (GBS) pathogenicity

Answer 7

Normal flora of fe- male genital tract. Most common cause of neonatal septicemia & meningitis

Question 8

Group B streptococci (GBS) key characteristics

Answer 8

Resistant to SXT & bacitracin. Sodium hippurate pos. CAMP pos.

Question 9

Group D streptococci, nonenterococci gram stain

Answer 9

Oval GPC in chains

Question 10

Group D streptococci, nonenterococci pathogenicity

Answer 10

Normal in GI tract. Causes nosocomial UTI, wound infections, bacteremia

Question 11

Group D streptococci, nonenterococci key characteristics

Answer 11

Hydrolyzes esculin

Question 12

Enterococcus gram stain

Answer 12

Oval GPC in pairs & chains

Question 13

Enterococcus pathogenicity

Answer 13

Normal in mouth, GI tract, female genital tract. Causes nosocomial UTI, wound infections, bacteremia

Question 14

Enterococcus key characteristics

Answer 14

Hydrolyzes esculin. Grows in 6.5% NaCl broth. PYR pos

Question 15

Streptococcus pneumoniae gram stain

Answer 15

(lancet-shaped) GPC. Usually in pairs

Question 16

Streptococcus pneumoniae pathogenicity

Answer 16

Most common cause

of community-acquired pneumonia. Major cause of otitis media, meningitis in adults. Infects sinuses, eyes

Question 17

Streptococcus pneumoniae key characteristics

Answer 17

Bile solubility pos. Sensitive to optochin

Question 18

Viridans streptococci gram stain

Answer 18

GPC in chains

Question 19

Viridans streptococci pathogenicity

Answer 19

Frequent cause of subacute bacterial endocarditis. Gingivitis & dental caries (cavities)

Question 20

Viridans streptococci key characteristics

Answer 20

Resistant to optochin. Bile solubility neg