Demonstration of reinfection and reactivation in HIV-negative autopsied cases of secondary tuberculosis: multilesional genotyping of Mycobacterium tuberculosis utilizing IS6110 and other repetitive element-based DNA fingerprinting

Setting Secondary tuberculosis may follow reinfection or endogenous reactiv ation. The design of effective preventive and treatment protocols requires knowledge about the relative importance of these mechanisms in specific com munities. Molecular typing of Mycobacterium tuberculosis has permitted link age of cases and demonstration of patterns of inter- or intrapatient strain diversity correlating with reinfection and reactivation. Objective: The use of DNA fingerprinting to examine intrapatient strain div ersity in autopsied, HIV-negative individuals resident in a high incidence community. Design: Autopsy (12 cases) and pneumonectomy (one case) permitted multilesi onal sampling for bacterial culture and comparative genotyping. Mycobacteri um tuberculosis strains were typed using probes directed against IS6110, th e direct repeat sequence (DR) and MTB484(1). Results: In two patients, the demonstration of pulmonary infection by two d istinct strains suggested dual infection of these individuals. In one other case, the strain isolated from a Ghon-focus was identical to that obtained from all secondary cavitating lesions, which suggested reactivation of the primary infection. In the remaining cases, all isolates were identical, bu t primary lesions could not be identified with certainty or were culture ne gative. One of these cases showed evidence of strain evolution. Conclusions: Multilesional strain genotyping suggested both reinfection and reactivation in a series of HIV-negative autopsied patients with secondary tuberculosis. In most (11/13) cases, the same strain (or clonal variant) w as present in all lesions, pulmonary and extrapulmonary. (C) 2001 Harcourt Publishers Ltd.