Deck 28: Eikenella and Similar Organisms

Question 1

Of the asaccharolytic, oxidase-positive bacilli that do not grow on MacConkey agar, which one of the following organisms is generally associated with mixed infections resulting from bites or clenched-fist wounds?

A) Eikenella corrodens
B) Weeksella virosa
C) Pseudomonas maltophilia
D) Sphingomonas paucimobilis

Answer 1

A
The organisms discussed in Chapter 29 are not commonly associated with human infections, but they are occasionally encountered in clinical specimens.Of those listed, E.corrodens is the one most commonly encountered and is usually found in mixed infections resulting from bites or clenched-fist wounds.

Question 2

Quality control performed on indole reagent should be performed on which two organisms?

A) Eikenella corrodens and Methylobacterium spp.
B) Weeksella virosa and Bergeyella zoohelcum
C) Bergeyella zoohelcum and Escherichia coli
D) Eikenella corrodens and Weeksella virosa

Answer 2

D
E.corrodens is indole-negative, and Weeksella virosa is indole-positive.The other combinations are either both indole-positive or both indole-negative.

Question 3

Eikenella corrodens can be easily recognized in culture by its:

A) pink pigmentation.
B) grapelike odor.
C) large spreading colonial morphologic characteristic.
D) bleachlike odor.

Answer 3

D
E.corrodens can be recognized in culture by its bleachlike odor.The organism does not utilize glucose or other carbohydrates and is catalase-negative.However, it reduces nitrate to nitrite and hydrolyzes both ornithine and lysine.

Question 4

Which of the following organisms is negative for catalase, indole, and arginine dihydrolase tests and pits the agar on a sheep blood agar plate?

A) Eikenella corrodens
B) Weeksella virosa
C) Pseudomonas maltophilia
D) Sphingomonas paucimobilis

Question 5

The organism that is found in vegetation and occasionally in the hospital environment grows best at which temperature?

A) 4º C
B) 25º C
C) 35º C
D) 56º C