AP-Micro Microbiology: Bacteriology: Gram-Negative Identification 2

Question 1

Which enzyme produced by Neisseria gonorrhoeae helps it evade complement-mediated killing?

Accepted Answer

IgA protease

Answer

Beta-lactamase

Answer

Catalase

Answer

Coagulase

Question 2

Which gram-negative rod is the most common cause of nosocomial urinary tract infections?

Accepted Answer

Escherichia coli

Answer

Klebsiella pneumoniae

Answer

Pseudomonas aeruginosa

Answer

Proteus mirabilis

Question 3

A gram-negative, oxidase-positive, non-fermenting rod growing at 42°C with a fruity odor is most likely:

Accepted Answer

Pseudomonas aeruginosa

Answer

Acinetobacter baumannii

Answer

Burkholderia cepacia

Answer

Stenotrophomonas maltophilia

Question 4

The Voges-Proskauer (VP) test detects which end-product of glucose fermentation?

Accepted Answer

Acetoin

Answer

Mixed acids

Answer

Hydrogen sulfide

Answer

Indole

Question 5

Which gram-negative organism characteristically produces a green metallic sheen on EMB agar?

Accepted Answer

Escherichia coli

Answer

Salmonella typhi

Answer

Enterobacter aerogenes

Answer

Klebsiella pneumoniae

Question 6

Haemophilus influenzae requires which two growth factors supplied in chocolate agar?

Accepted Answer

Factors V and X

Answer

Factors I and II

Answer

Factors X and Y

Answer

Factors II and V

Question 7

Which characteristic distinguishes Shigella from Salmonella on triple sugar iron (TSI) agar?

Accepted Answer

Shigella produces no gas; Salmonella typically produces gas

Answer

Shigella produces H2S; Salmonella does not

Answer

Shigella ferments lactose; Salmonella does not

Answer

Shigella alkalinizes the slant; Salmonella acidifies it