Deck 22: Rhizobium, Ochrobactrum, and Similar Organisms

Question 1

Which two organisms should be used to determine the validity of the nitrate reduction test?

A) Achromobacter and Alcaligenes
B) Psychrobacter and Rhizobium
C) CDC group Ic and CDC group O-3
D) CDC group OFBA-1c and Shewanella

Answer 1

C
The only two organisms that are positive and negative for nitrate reduction are CDC group Ic and CDC group O-3, respectively.

Question 2

Which organism is a nonlactose-fermenter that oxidizes glucose and xylose and also morphologically resembles colonies of Enterobacteriaceae?

A) CDC group Ic
B) Ochrobactrum anthropi
C) Shewanella putrefaciens
D) Alcaligenes xylosoxidans

Answer 2

B
Morphologically, O.anthropi resemble colonies of Enterobacteriaceae, only smaller, and is a nonlactose-fermenting organism.

Question 3

Which of the following organisms is oral and respiratory flora of animals and is transmitted by bites or scratches from dogs and cats?

A) Achromobacter group
B) Alcaligenes xylosoxidans
C) Paracoccus yeei
D) Centers for Disease Control and Prevention (CDC) group EF-4b

Answer 3

D
CDC group EF-4b is animal oral and respiratory flora; it is not part of human flora and is transmitted by animal contact, particularly bites or scratches from dogs and cats.

Question 4

The natural habitat of Achromobacter 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 5

A patient with an indwelling catheter tip began spiking a fever of 39º C.The site of the catheter was inflamed and red.The catheter tip was cultured, and the following organism was isolated: a nonlactose-fermenter on MacConkey agar; a glucose, xylose, and mannitol oxidizer with the ability to hydrolyze esculin.This organism is most likely which one of the following?

A) CDC group EF-4b
B) Shewanella putrefaciens
C) Rhizobium radiobacter
D) Paracoccus yeei

Question 6

The most common type of infection caused by both Rhizobium radiobacter and Ochrobactrum anthropi is:

A) peritonitis.
B) endocarditis.
C) meningitis.
D) bacteremia.

Question 7

The reservoir for Ochrobactrum anthropi is:

A) environment only, not human flora.
B) animal oral and respiratory flora.
C) environment, cold climates.
D) environment and human flora.

Question 8

Which of the following organisms has clear colonies on MacConkey agar, oxidizes glucose and xylose, and has the ability to hydrolyze esculin?

A) Alcaligenes xylosoxidans
B) Paracoccus yeei
C) Rhizobium radiobacter
D) Shewanella putrefaciens

Question 9

Which nonlactose-fermenting organism that rarely causes human infection, grows poorly at 35º C; however, grows optimally between 20º and 25º C?

A) Psychrobacter immobilis
B) Alcaligenes xylosoxidans
C) Rhizobium radiobacter
D) Shewanella putrefaciens

Question 10

Although validated susceptibility testing methods do not exist for this group of organisms, in vitro data suggest that certain cephalosporins and aminoglycosides are effective against which one of the following groups of organisms?

A) Ochrobactrum anthropi
B) Shewanella putrefaciens
C) Paracoccus yeei
D) Rhizobium radiobacter