Deck 26: Moraxella

Question 1

In Gram-stained preparations,M.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.

Answer 1

A
Other than Gram stain of patient specimens,no specific procedures are performed for the direct detection of these organisms in clinical material.M.atlantae,Moraxella nonliquefaciens,and Moraxella osloensis may appear either as coccobacilli or as short,broad rods that tend to resist decolorization and may appear gram-variable.This appearance is also evident for M.canis,which appears as cocci in pairs or short chains.M.lacunata is a coccobacillus or medium-sized rod,and Moraxella lincolnii is a coccobacillus that may appear in chains.All subspecies of Neisseria elongata are either coccobacilli or short,straight rods,and Neisseria weaverii is a medium-length,straight bacillus.

Question 2

Testing for differentiation of M.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 2

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

Question 3

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

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

Answer 3

A
M.catarrhalis is the species most commonly associated with human infections,primarily of the respiratory tract.

Question 4

True cocci,such as most Neisseria spp.and Moraxella 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 b-lactam antimicrobial agents.
D)performing the deoxyribonucleic acid (DNA)test.

Question 5

Testing for differentiation of M.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 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

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

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

Question 8

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

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

Question 9

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.

Question 10

In Gram-stained preparations,M.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 11

The commensal Neisseria spp.are often confused with pathogenic gram-negative diplococci.A simple test utilizing a blood agar plate and an antibiotic disk resulting in elongation of the cells assists in the differentiation of these organisms.Which antibiotic disk is utilized in this application?

A)Cephalosporin
B)Vancomycin
C)Penicillin
D)Metronidazole