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Nocardia, Rhodococcus

Microbiology Notes Nocardia, Rhodococcus

Gram (+)
Branching
Partially acid-fast

Nocardia

Characteristics

Beaded appearance
Strictly aerobic
Presence of DAP
Produces Nocobactin – ironchelating compound
Urease (+)

Disease association

Cutaneous infection
Actinomycotic mycetoma

Nocardia brasiliensis – most common cause of cutaneous infection and actinomycotic mycetoma.

Nocardia asteroides – causes pulmonary infection

Organism	Casein Hydrolysis
Nocardia brasilisiensis	+
Nocardia asteroides	–

Rhodococcus equi

Characteristics

Facultative intracellular organism; replicate within macrophage.
Salmon-pink pigment
Cocci to rods – 24 hours
CAMP (+) w/ S. aureus

Disease association

Infections in immunocompromised patients such as patients with HIV

Test	Nocardia	Actinomyces spp.
O2 requirement	Aerobic	Anaerobic
AFS	Acid-fast	Non acid-fast
Catalase	+	–
Urease	+	–
Sulfur Granules	+	+

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