Deck 20: Acinetobacter, Stenotrophomonas, and Other Organisms

Question 1

Which organism is oxidase-negative, oxidizes glucose, and is a nonlactose fermenter?

A) Escherichia
B) Pseudomonas
C) Acinetobacter
D) Moraxella

Answer 1

C
The organisms discussed in this chapter are considered together because, except for the Centers for Disease and Control (CDC)group NO-1, they are all oxidase negative and grow on MacConkey agar, as do the Enterobacteriaceae family.However, unlike the Enterobacteriaceae family, which ferments glucose, these organisms either oxidize or do not use glucose.

Question 2

For more serious infections caused by Acinetobacter spp., such as pneumonia or bacteremia, effective treatment may require the use of:

A) multiple rounds of penicillin or a similar antibiotic.
B) a beta-lactam agent in combination with an aminoglycoside antibiotic.
C) repeated high-level doses of gentamycin.
D) single-drug therapy in combination with a steroid.

Answer 2

B
For urinary tract infections caused by Acinetobacter spp., single-drug therapy is usually sufficient.In contrast, more serious infections, such as pneumonia or bacteremia, may require the use of a beta-lactam agent in combination with an aminoglycoside antibiotic.

Question 3

A bronchoscopy was performed on a patient who later developed a nosocomial infection as a result of the procedure.The organism recovered from his lung was a nonlactose fermenter that oxidized glucose and maltose, was lysine decarboxylase-positive, and was motile.The organism is most likely which one of the following?

A) Bordetella parapertussis
B) Saccharolytic Acinetobacter
C) Pseudomonas luteola
D) Stenotrophomonas maltophilia

Answer 3

D

Question 4

Plump coccobacilli that tend to resist alcohol decolorization and may be mistaken for Neisseria spp.are:

A) Bordetella spp.
B) Stenotrophomonas maltophilia.
C) Acinetobacter spp.
D) Pseudomonas oryzihabitans.

Question 5

The primary drug of choice for infections caused by Stenotrophomonas maltophilia is:

A) a beta-lactam agent in combination with an aminoglycoside antibiotic.
B) trimethoprim-sulfamethoxazole.
C) ticarcillin and clavulanic acid.
D) chloramphenicol.

Question 6

The natural habitat of Acinetobacter sp.can best be described as the:

A) mucous membranes of animals.
B) gastrointestinal tract of humans and other animals.
C) natural environment.
D) genitourinary tract of animals.

Question 7

Which organism may be mistaken for a lactose fermenter on MacConkey agar because of colonies exhibiting a purple hue on the media?

A) Acinetobacter spp.
B) Pseudomonas luteola
C) Stenotrophomonas maltophilia
D) Bordetella holmesii

Question 8

Of the following species, which are widely distributed in nature and hospital environments?

A) Pseudomonas luteola
B) Acinetobacter spp.
C) Pseudomonas oryzihabitans
D) Bordetella trematum

Question 9

Differentiation of Stenotrophomonas maltophilia and Burkholderia cepacia is best accomplished by:

A) the oxidase test.
B) maltose and glucose medium.
C) tyrosine-enriched heart infusion agar.
D) nitrate reduction.

Question 10

Which organism is often isolated in the sputum of patients with cystic fibrosis?

A) Acinetobacter spp.
B) Bordetella trematum
C) Burkholderia gladioli
D) Stenotrophomonas maltophilia