Impact of HIV Infection on the Recurrence of Tuberculosis in South India

BACKGROUND: There is limited information on the relative proportion of reactivation and reinfection at the time of recurrence among human immunodeficiency virus (HIV)-infected and HIV-uninfected patients who are successfully treated for tuberculosis infection in India. METHODS: HIV-infected and HIV-uninfected patients with sputum culture-positive pulmonary tuberculosis were treated with short-course regimens and followed up for 36 months at the Tuberculosis Research Centre South India. Bacteriologic recurrences were documented and typing of strains was performed using 3 different genotypic techniques: restriction fragment length polymorphism (RFLP) by IS6110 spoligotyping and mycobacterial interspersed repeat unit (MIRU)-variable number tandem repeat (VNTR). DNA fingerprints of paired Mycobacterium tuberculosis isolates (baseline and recurrence) were compared. RESULTS: Among 44 HIV-infected and 30 HIV-uninfected patients with recurrent tuberculosis during the period July 1999 to October 2005 25 and 23 paired isolates respectively were typed using all 3 methods. Recurrence was due to exogenous reinfection in 88% of HIV-infected and 9% of HIV-uninfected patients (P<.05). Among recurrent isolates the HIV-infected patients showed more clustering as well as a higher proportion of drug resistance including multidrug resistance. CONCLUSIONS: In India a tuberculosis-endemic country most recurrences after successful treatment of tuberculosis are due to exogenous reinfection in HIV-infected persons and endogenous reactivation in HIV-uninfected persons. Strategies for prevention and treatment of tuberculosis infection must take these findings into consideration.