Nocardiosis

[Tariq Zaki]

Nocardiosis is an acute or chronic, often disseminated, suppurative or granulomatous infection caused by various aerobic soil saprophytes of the genus Nocardia. Pneumonia is typical, but skin and central nervous system infections are common. Diagnosis is by culture and special stains. Treatment is usually with sulfonamides.
Nocardia are obligate aerobic, partially acid-fast, beaded, branching, gram-positive bacilli. The genus Nocardia, in the family Actinomycetaceae, has many species and an increasing number are recognized as causes of human disease.
N. asteroides usually causes pulmonary and disseminated infection.
N. brasiliensis most commonly causes skin infection, particularly in tropical climates. Infection is via inhalation or by direct inoculation of the skin.
Other Nocardia species sometimes cause localized or, occasionally, systemic infections.
Nocardiosis occurs worldwide in all age groups, but incidence is higher in older adults, especially men, and immunocompromised patients. Person-to-person spread is rare.
Nocardia is found in standing water, decaying plants, and soil. Infection is via inhalation of dust that contains the bacteria or by direct inoculation of the skin when contaminated soil or water enters through a cut or scrape.

[Dianne]

Disease caused by Nocardia species, especially N. asteroides, chiefly seen in immunocompromised individuals and typically beginning with abscess formation in the lungs or in the skin, sometimes spreading to other organs, especially the brain.