Deck 28: Eikenella Corrodens and Similar Organisms

Question 1

Eikenella corrodens can be easily recognized in culture by which characteristic?

A)Its pink pigmentation
B)Its grapelike odor
C)Its large spreading colony morphology
D)Its bleachlike odor

Answer 1

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 2

Of the asaccharolytic, oxidase-positive bacilli that do not grow on MacConkey agar, which one is among the HACEK group of bacteria known to cause subacute bacterial endocarditis?

A)Eikenella corrodens
B)Weeksella virosa
C)Pseudomonas maltophilia
D)Sphingomonas paucimobilis
E)All of the above are correct.

Answer 2

A
The organisms discussed in Chapter 31 are not commonly associated with human infections, but they are occasionally encountered in clinical specimens. Of those listed, Eikenella corrodens is the one most commonly encountered and is the "E," for Eikenella, among the HACEK group of bacteria known to cause subacute bacterial endocarditis.

Question 3

Valid susceptibility testing methods are not available for

A)Enterobacteriaceae.
B)Pseudomonas.
C)Eikenella.
D)Staphylococcus.

Answer 3

C
The rarity with which these organisms are encountered as the cause of infection and the lack of validated in vitro susceptibility testing methods do not allow definitive treatment guidelines to be given for most of them. Although beta-lactamase production has been described in E. corrodens, this species is usually susceptible to penicillins and many other beta-lactam antimicrobials so that therapy with these agents is frequently used.

Question 4

Of the asaccharolytic, oxidase-positive bacilli that do not grow on MacConkey agar, which one 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
E)All of the above are correct.

Question 5

Of the asaccharolytic, oxidase-positive bacilli, which bacterial species can be recognized in culture by its bleachlike odor?

A)Eikenella corrodens
B)Weeksella virosa
C)Pseudomonas maltophilia
D)Sphingomonas paucimobilis
E)All of the above are correct.