Unusual nosocomial transmission of Mycobacterium tuberculosis.

This case report describes how a late diagnosis of a tuberculous abscess combined with daily irrigation of the wound without barrier precautions led to nosocomial transmission of Mycobacterium tuberculosis. Among 372 hospital contacts, 16 had a tuberculin skin test conversion and two developed active pulmonary tuberculosis with the same strain as that isolated from the index patient's abscess. When a culture from an abscess remains negative, Mycobacterium tuberculosis infection should be considered. Furthermore, wound irrigation should be done with proper barrier precautions because infectious aerosols can be created during the irrigation process.