[Exogenous reinfection with Mycobacterium tuberculosis caused by nosocomial transmission by a patient with AIDS].

A 55-year-old AIDS patient relapsed with tuberculosis as a result of exogenous reinfection, 1.5 years after a prior diagnosis of tuberculosis, for which he had been treated. He was reinfected after exposure to another AIDS patient, a 25-year-old man with tuberculosis, when they were hospitalized together during 5 days. The diagnosis of tuberculosis in the latter patient was delayed because the clinical picture was obscured by another infection. Reinfection and nosocomial transmission were demonstrated by analysis of the restriction-fragment-length polymorphism patterns on serial isolates of Mycobacterium tuberculosis. Increased alertness to tuberculosis, especially among HIV-infected persons, and implementation of effective infection control precautions are important in the prevention of nosocomial transmission.