A high rate of recurrent tuberculosis in western Kenya independent of human immunodeficiency virus infection

Abstract

Background: Previous studies have shown that recurrent TB develops in about 2-5% of the patients after curative treatment with short-course anti-TB chemotherapy. With the advent of HIV/AIDS, the rate TB recurrence is anticipated to rise.

Objectives: To determine whether HIV infection and TB recurrence are associated with anti-TB drug resistance and the rates of ZN microscopy and culture positivity among the recurrent TB cases in western Kenya. Design and methods: A cross-sectional study was carried out between 2007 and 2009. Sputa from 872 tuberculosis suspects underwent mycobacteriologic evaluation using Ziehl Neelsen smear microscopy, LowensteinJensen and BACTEC MGIT 960 culturing, and Hain’s GenoType^® Mycobacterium CM and GenoType^® Mycobacterium AS molecular identification tests. Consenting participants were screened for HIV infection using Uni-Gold TM test and positives were confirmed with the enzyme linked immunosorbent assay.

Results: In total, 361/872 (41%) of the suspects mycobacterial disease (346 TB, 4.2% non-tuberculous mycobacterial disease). HIV testing was accepted by 695 (79.7%) and 39.1% of these (272/695) were found positive. Recurrence of TB constituted 44.8% (155/346) of the TB cases, with 41.9% (65/155) of them co-infected with HIV. There was nosignificant difference in TB recurrence rates with HIV status [OR = 0.57; 95% CI: 0.29-1.13; P = 0.10].

Conclusions and recommendations: This study reports a much higher (44.8%) rate of recurrent TB, compared to that of National TB control Programme of 5% in 2008 and a combined retreatment rate of 14% in 2009. The HIV co-infection and TB recurrence were not associated with anti-TB drug resistance. The majority of TB recurrent cases were ZN smear negative (67.7%) and culture negative (80%). The high TB recurrence observed in this study calls for studies to determine the proportions of the disease attributable to endogenous re-activation (relapse) and exogenous re-infection.

Keywords: Recurrent tuberculosis; HIV co-infection