Question 1

Nocardia spp.form branched filaments that extend along the agar surface that are called&#10;A)surface hyphae.&#10;B)substrate hyphae.&#10;C)aerial hyphae.&#10;D)topical hyphae.

Accepted Answer

Nocardia spp. form branched fillaments that extend along the agar surface (substrate hyphae) and into the air (aerial hyphae).

Question 2

The organism that has been most commonly associated with human disease, particularly in immunocompromised patients, such as those infected with human immunodeficiency virus (HIV) is&#10;A)Rhodococcus.&#10;B)Gordonia.&#10;C)Tsukamurella.&#10;D)Streptomyces.

Accepted Answer

Rhodococcus equi has been the organism most commonly associated with human disease, particularly in immunocompromised patients, such as those infected with human immunodeficiency virus (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 3

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&#10;A)Rhodococcus.&#10;B)Nocardia.&#10;C)Gordonia.&#10;D)Tsukamurella.

Accepted Answer

Nocardia are normal inhabitants of soil and water, and are primarily responsible for the decomposition of plant material. Infections caused by Nocardia spp. are found worldwide. Because they are ubiquitous, the isolation of these organisms from clinical specimens does not always indicate infection.

Question 4

A chronic, granulomatous infection of subcutaneous tissues caused by aerobic actinomycetes resulting in tissue swelling and draining sinus tracts are referred to as&#10;A)actinomycetoma.&#10;B)infectious granulomas.&#10;C)lymphocytoma.&#10;D)Actinomadura.

Accepted Answer

Infection caused by most non-acid-fast aerobic actinomycetes is usually chronic, granulomatous lesions of the skin referred to as mycetoma. Mycetoma is an infection of subcutaneous tissues resulting in tissue swelling and draining sinus tracts. These infections are acquired by traumatic inoculation of organisms (usually in the lower limbs) and are usually caused by fungi. If a mycetoma is caused by an actinomycete, the infection is then called actinomycetoma.

Question 5

Nocardia spp.cause which of the following types of infections in immunocompromised individuals?&#10;A)Mycetoma&#10;B)Lymphocutaneous infections&#10;C)Skin abscesses or cellulites&#10;D)Invasive pulmonary infections

Accepted Answer

Nocardia spp. cause three types of skin infections in immunocompetent individuals: (1) mycetoma, a chronic, localized, painless, subcutaneous infection, (2) lymphocutaneous infections, and (3) skin abscesses or cellulites. In individuals who are immunocompromised, Nocardia spp. can cause invasive pulmonary infections and disseminated infections.

Question 6

Partially acid-fast aerobic actinomycetes include&#10;A)Nocardia.&#10;B)Rhodococcus&#10;C)Gordona&#10;D)Tsukamurella&#10;E)All of the above are correct.

Accepted Answer

The genera Nocardia, Rhodococcus, Gordonia, and Tsukamurella are all partially acid-fast aerobic actinomycetes

Question 7

Nocardia spp.form branched filaments that extend into the air that are called&#10;A)surface hyphae.&#10;B)substrate hyphae.&#10;C)aerial hyphae.&#10;D)topical hyphae.

Accepted Answer

Nocardia spp. form branched filaments that extend along the agar surface (substrate hyphae) and into the air (aerial hyphae).

Question 8

Non-acid-fast aerobic actinomycetes include&#10;A)Nocardia.&#10;B)Rhodococcus.&#10;C)Streptomyces.&#10;D)Gordona.&#10;E)All of the above are correct.

Accepted Answer

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

Question 9

Nocardia spp.cause which of the following types of infections in immunocompetent individuals?&#10;A)Urinary tract infections&#10;B)Disseminated infections&#10;C)Skin abscesses or cellulites&#10;D)Invasive pulmonary infections

Accepted Answer

Nocardia spp. cause three types of skin infections in immunocompetent individuals: (1) mycetoma, a chronic, localized, painless, subcutaneous infection, (2) lymphocutaneous infections, and (3) skin abscesses or cellulites. In individuals who are immunocompromised, Nocardia spp. can cause invasive pulmonary infections and disseminated infections.

Question 10

Nocardia have as part of their cell wall peptidoglycan&#10;A)mesodiaminopimelic acid (DAP).&#10;B)arabinose.&#10;C)galactose.&#10;D)All of the above are correct.

Accepted Answer

Nocardiae are characterized by the presence of mesodiaminopimelic acid (DAP) and the sugars arabinose and galactose in their cell wall peptidoglycan.

Deck 18: Nocardia, Streptomyces, Rhodococcus, Oerskovia, and Similar Organisms