Deck 17: Nocardia, Streptomyces, Rhodococcus, Oerskovia, and Similar Organisms

Question 1

The organism that has been most commonly associated with human disease,particularly in patients who are immunocompromised,such as those infected with human immunodeficiency virus (HIV),is:

A)Rhodococcus.
B)Gordonia.
C)Tsukamurella.
D)Streptomyces.

Answer 1

A
Rhodococcus equi has been the organism most commonly associated with human disease,particularly in patients who are immunocompromised,such as those infected with HIV.R.equi is a facultative intracellular organism that can persist and replicate within macrophages.Determinants of virulence of R.equi are under investigation and may involve cell wall mycolic acids that play a role in intracellular survival,production of interleukin 4,and granuloma formation.

Question 2

Non-acid-fast aerobic actinomycetes include:

A)Nocardia.
B)Rhodococcus.
C)Streptomyces.
D)Gordona.

Answer 2

C
Streptomyces,Actinomadura,Dermatophilus,Nocardiopsis,and the thermophilic Actinomycetes are gram-positive,branching filaments that do not have mycolic acids present in their cell envelopes and are therefore non-acid-fast.

Question 3

Nocardia spp.form branched filaments that extend into the air that are called _____ hyphae.

A)surface
B)substrate
C)aerial
D)topical

Answer 3

C
Nocardia spp.form branched filaments that extend into the air and are referred to as aerial hyphae.

Question 4

Nocardia spp.form branched filaments that extend along the agar surface,which are called _____ hyphae.

A)surface
B)substrate
C)aerial
D)topical

Question 5

Partially acid-fast aerobic actinomycetes include:

A)Nocardia.
B)Mycobacteria.
C)Streptomyces.
D)Actinomadura.

Question 6

A chronic,granulomatous infection of subcutaneous tissues,which is caused by aerobic actinomycetes resulting in tissue swelling and draining sinus tracts,is referred to as:

A)actinomycetoma.
B)infectious granulomas.
C)lymphocytoma.
D)Actinomadura.

Question 7

Nocardia spp.cause which of the following types of infections in individuals who are immunocompromised?

A)Mycetoma
B)Lymphocutaneous infections
C)Skin abscesses or cellulites
D)Invasive pulmonary infections

Question 8

The group of bacteria that can be described as being normal inhabitants of soil and water and primarily responsible for the decomposition of plant material is:

A)Rhodococcus.
B)Nocardia.
C)Gordonia.
D)Tsukamurella.

Question 9

Which organisms should be used to run quality control for acid-fast stains?

A)Nocardia and Rhodococcus
B)Streptomyces and Actinomadura
C)Dermatophilus and Nocardiopsis
D)Nocardia and Streptomyces

Question 10

Which partially acid-fast,gram-positive,and branching filamentous bacteria appear dry and white to creamy to orange with rhizoid edges on routine agar and are urea-positive and resistant to lysozyme?

A)Tsukamurella
B)Gordonia
C)Actinomadura
D)Dermatophilus