Major Bacterial Genera Study Guide With Questions And Complete Answers [Graded A+]

MAJOR BACTERIAL GENERA STUDY

GUIDE WITH QUESTIONS AND

COMPLETE ANSWERS [GRADED A+]



Staphylococcus aureus - ✔✔Gram positive cocci

Catalase positive

Staphylococci - Facultative anaerobe

Coagulase (+)

Normal flora on skin and in nares

Colonies often yellow

Salt tolerant

Produce acid from mannitol



S. epidermidis - ✔✔Gram positive cocci

Catalase positive

Staphylococci - Facultative anaerobe

Coagulase (-)


©morren2025/2026.Year published 2026.

,Normal flora on skin, nares, vagina

Novobiocin susceptible



S. saprophyticus - ✔✔Gram positive cocci

Catalase positive

Staphylococci - Facultative anaerobe

Coagulase (-)

Normal flora on skin, nares, vagina

Novobiocin resistant



Enterococcus - ✔✔Gram positive cocci

Catalase (-)

Anaerobe

Non-hemolytic (Gamma)

Lancefield Group D

Black colonies on bile-esculin agar

Normal GI flora



Streptococcus - ✔✔Gram positive cocci

Catalase (-)


©morren2025/2026.Year published 2026.

, Anaerobe

Non-hemolytic (Gamma)

Clear colonies with no growth on bile-esculin agar



Streptococcus agalactiae - ✔✔Gram positive cocci

Catalase (-)

Anaerobe

Beta-hemolytic

Bacitracin resistant

PYR (-)

Lancefield group B



Streptococcus pyogenes - ✔✔Gram positive cocci

Catalase (-)

Anaerobe

Beta-hemolytic

Bacitracin susceptible

PYR (+)

Lancefield group A

Can be part of the normal pharyngeal flora


©morren2025/2026.Year published 2026.