infectious diseases
Nocardiosis
Introduction
Nocardiosis is an acute or chronic, often disseminated, suppurative or granulomatous infection caused by various aerobic soil saprophytes of the gram-positive bacilli genusNocardia. Pneumonia is typical, but skin and central nervous system infections are common. Diagnosis is by culture and special stains. Treatment is usually with sulfonamides. Nocardiaare obligate aerobic, partially acid-fast, beaded, branching, gram-positive bacilli. The genusNocardiahas many species and an increasing number are recognized as causes of human disease. N. asteroidesusually causes pulmonary and disseminated infection. N. brasiliensismost commonly causes skin infection, particularly in tropical climates. Infection is via inhalation or by direct inoculation of the skin. OtherNocardiaspecies 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. Nocardiais 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. 