Deck 27: Moraxella and Related Organisms

Question 1

Testing for differentiation of Moraxella nonliquefaciens and M.osloensis can best be performed by:

A) the ability to utilize acetate.
B) the ability to liquefy serum.
C) glucose utilization tests.
D) growth on MacConkey agar.

Answer 1

A
The ability of M.osloensis to utilize acetate can differentiate M.nonliquefaciens and M.osloensis.

Question 2

Which organism appears clear on MacConkey agar and resembles some colonies of the Enterobacteriaceae family?

A) Moraxella lacunata
B) M. lincolnii
C) M. canis
D) M. nonliquefaciens

Answer 2

C
M.canis is a nonlactose fermenter, appears clear on MacConkey agar, and resembles some colonies of the Enterobacteriaceae family.

Question 3

Quality control should be performed on which two organisms to determine the validity of deoxyribonuclease (DNase)media?

A) Moraxella atlantae and M. lacunata
B) M. lacunata and M. lincolnii
C) M. nonliquefaciens and M. canis
D) M. osloensis and M. lacunata

Answer 3

C
M.nonliquefaciens and M.canis are the only two organisms that are negative and positive, respectively, for DNase activity.All other organisms listed are DNase-negative.

Question 4

In Gram-stained preparations, Moraxella lacunata will appear as:

A) either gram-negative coccobacilli or short, broad rods that tend to resist decolorization and may appear gram-variable.
B) gram-negative cocci in pairs or short chains.
C) coccobacilli or medium-sized rods.
D) coccobacilli that may appear in chains.

Question 5

In Gram-stained preparations, Moraxella atlantae will appear as:

A) either gram-negative coccobacilli or short, broad rods that tend to resist decolorization and may appear gram-variable.
B) gram-negative cocci in pairs or short chains.
C) coccobacilli or medium-sized rods.
D) coccobacilli that may appear in chains.

Question 6

Which of the following tests can be performed to differentiate the two subspecies of Neisseria-elongata and glycolytica?

A) Catalase
B) Nitrate reduction
C) DNase
D) Growth in nutrient broth

Question 7

True cocci, such as most Neisseria spp.and Moraxella (Branhamella)catarrhalis, can be differentiated from morphologically similar Moraxella species by:

A) comparing the penicillin susceptibility testing results of the bacteria.
B) subjecting the bacterium to noninhibitory concentrations of penicillin.
C) identifying the resistance of Moraxella to many beta-lactam antimicrobial agents.
D) performing the deoxyribonucleic acid (DNA) test.

Question 8

Testing for differentiation of Moraxella lacunata from other Moraxella species can best be performed by:

A) the ability to utilize acetate.
B) the ability to liquefy serum.
C) glucose utilization tests.
D) growth on MacConkey agar.

Question 9

The species of Moraxella that is most commonly associated with human infections, primarily of the respiratory tract, is:

A) M. catarrhalis.
B) M. lacunata.
C) M. canis.
D) M. atlantae.

Question 10

The virulence of this organism(s), which is transmitted via a dog bite, is attributed to:

A) protease production.
B) various toxins.
C) hemolysins.
D) something unknown.