Deck 29: Actinobacillus, Kingella, Cardiobacterium, Capnocytophaga, and Similar Organisms

Question 1

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

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

Answer 1

B
Capnocytophaga spp.can be identified with the isolation of a yellow-pigmented,thin,gram-negative rod with tapered ends that exhibits gliding motility and does not grow in ambient air.

Question 2

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

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

Answer 2

D
These organisms are part of the normal flora of humans and other animals.As such,they are generally of low virulence.Except for those species associated with periodontal infections,these organisms usually only cause infections in humans after an introduction into sterile sites after trauma such as bites or manipulations in the oral cavity.

Question 3

K.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)C.hominis
C)A.aphrophilus
D)N.gonorrhoeae

Answer 3

D
Kingella spp.are catalase-negative,which helps separate them from Neisseria spp.(see Chapter 40),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 4

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.

Question 5

Of the following organisms,which one is among the Aggregatibacter 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)E.corrodens
D)A.actinomycetemcomitans

Question 6

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

A)A.actinomycetemcomitans and Kingella kingae
B)C.hominis and A.aphrophilus
C)K.denitrificans and K.kingae
D)Actinobacillus suis and Actinobacillus ureae

Question 7

Which antimicrobial regimen should be administered to a patient suspected of having endocarditis as a result of infection with C.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 a-hemolytic after 48 hours and is commonly associated with individuals with anatomic heart defects?

A)K.kingae
B)C.hominis
C)A.suis
D)Capnocytophaga spp.

Question 9

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

Question 10

A.actinomycetemcomitans can be distinguished from A.aphrophilus by its:

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