An investigation of suspected exogenous reinfection in tuberculosis patients in Kampala, Uganda.

Exogenous reinfection with Mycobacterium tuberculosis is an important phenomenon that occurs with unknown frequency in both immunocompromised and immunocompetent persons. As previous investigations suggest that exogenous reinfection can occur in both of these populations, we reviewed data for 40 cases of suspected TB relapse in an attempt to determine the frequency of this phenomenon in patients treated at the TB Research Unit in Kampala, Uganda. Our findings suggest that while this entity can occur in immunocompetent persons, immunocompromised persons are probably at higher risk for exogenous reinfection with M. tuberculosis.