RECURRENCE OF HIV-RELATED TUBERCULOSIS IN AN ENDEMIC AREA MAY BE DUE TO RELAPSE OR REINFECTION

Setting: Two Research Clinics within Nairobi, Kenya, one in the Infect ious Diseases Hospital, the national referral centre for tuberculosis, and one in a community based project in Pumwani district, and the Bac terial Molecular Genetics Unit at the London School of Hygiene and Tro pical Medicine. Objective: To determine whether recurrence of tubercul osis after 'adequate' treatment was due to reinfection with a differen t isolate of Mycobacterium tuberculosis or to relapse of the original infection. Design: A retrospective comparison by DNA fingerprinting of sets of isolates of M. tuberculosis from patients with recurrence of tuberculosis and in whom isolates from the original episode had been s tored was made. Five patients with recurrence of tuberculosis two to n ineteen months after adequate treatment and documented clearance of di sease were studied. Results: In one patient, fingerprints of the isola tes of M. tuberculosis from the recurrence were quite different to tho se from the original episode; in the other four, the fingerprints were identical. Conclusion: Reinfection rather than relapse was the cause of recurrence in at least one patient. The high 'relapse' rates seen i n HIV-related tuberculosis in Africa may in part be due to increased s usceptibility to reinfection and not to treatment failure.