Deck 30: Actinobacillus, Aggregatibacter, Kingella, Cardiobacterium, Capnocytophaga, and Similar Organisms

Question 1

Kingella spp.can be distinguished from Neisseria spp.by its:

A) negative test for catalase.
B) positive test for lactose fermentation.
C) positive test for catalase.
D) negative test for oxidase.

Answer 1

A
Kingella spp.are catalase-negative, which helps separate them from Neisseria spp., with which they are sometimes confused.K.denitrificans may be mistaken for N.gonorrhoeae when isolated from modified Thayer-Martin agar.Nitrate reduction is a key test in differentiating K.denitrificans from N.gonorrhoeae, which is nitrate-negative.

Question 2

Of the following organisms, which one is among the Haemophilus aphrophilus, Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella spp.(HACEK)group of organisms that cause slowly progressive bacterial endocarditis?

A) Capnocytophaga gingivalis
B) Sphingomonas paucimobilis
C) Eikenella corrodens
D) Aggregatibacter actinomycetemcomitans

Answer 2

D
The types of infections caused by the bacteria in Chapter 31 vary from periodontitis to endocarditis.Three of these organisms, Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, and Kingella spp., are the A, C, and K, respectively, of the HACEK group of organisms that cause slowly progressive bacterial endocarditis.

Question 3

To test the validity of catalase reagent, which two organisms should be used?

A) Aggregatibacter actinomycetemcomitans and Kingella kingae
B) Cardiobacterium hominis and Aggregatibacter aphrophilus
C) Kingella denitrificans and Kingella kingae
D) Actinobacillus suis and Actinobacillus ureae

Answer 3

A
Only A.actinomycetemcomitans and K.kingae are positive and negative for catalase, respectively.C.hominis, A.aphrophilus, K.denitrificans, and K.kingae are catalase-negative, and both A.suis and A.ureae are variable for catalase.

Question 4

Kingella denitrificans, which is nonhemolytic and tends to pit the agar, also grows on selective media that support the growth of which gram-negative diplococci?

A) Capnocytophaga spp.
B) Cardiobacterium hominis
C) Aggregatibacter aphrophilus
D) Neisseria gonorrhoeae

Question 5

Which organism can cause granulomatous disease in animals and has been associated with soft-tissue infection in humans after animal bites?

A) Sphingomonas paucimobilis
B) Weeksella virosa
C) Pasteurella multocida
D) Actinobacillus spp.

Question 6

Which yellow-pigmented organism exhibits gliding motility that grows best at 35º C and in conditions with increased carbon dioxide (CO₂)but cannot grow in ambient air?

A) Actinobacillus
B) Capnocytophaga
C) Cardiobacterium
D) Kingella

Question 7

Which antimicrobial regimen should be administered to a patient suspected of having endocarditis as a result of infection with Cardiobacterium hominis?

A) Chloramphenicol and tetracycline
B) Erythromycin and ciprofloxacin
C) Ampicillin and ceftriaxone
D) Penicillin, with or without an aminoglycoside agent

Question 8

Which organism is slightly alpha-hemolytic after 48 hours and is commonly associated with individuals with anatomic heart defects?

A) Kingella kingae
B) Cardiobacterium hominis
C) Actinobacillus suis
D) Capnocytophaga spp.

Question 9

Aggregatibacter actinomycetemcomitans can be distinguished from Aggregatibacter aphrophilus by its:

A) negative test for catalase.
B) positive test for lactose fermentation.
C) positive test for catalase.
D) negative test for oxidase.

Question 10

Which of the following biochemical reactions identifies an organism associated with blood, bone, and joint infections in young children?

A) Positive catalase, positive nitrate reduction, and positive indole
B) Negative catalase, positive nitrate reduction, and positive indole
C) Negative catalase, negative nitrate reduction, and positive indole
D) Negative catalase, negative nitrate reduction, and negative indole