Impact of mycobacterial culture among HIV-infected adults with presumed TB in Uganda: a prospective cohort study.

Abstract

Implementation of new tuberculosis (TB) diagnostic strategies in resource-constrained settings is challenging. We measured the impact of solid and liquid mycobacterial cultures on treatment practices for patients undergoing TB evaluation in Kampala, Uganda. We enrolled consecutive smear-negative, human immunodeficiency virus positive adults with cough of ⩾2 weeks from September 2009 to April 2010. Laboratory technicians performed mycobacterial cultures on solid and liquid media. We compared empiric treatment decisions with solid and liquid culture in terms of diagnostic yield and time to results, and assessed impact on patient management. Of 200 patients enrolled, 26 (13%) had culture-confirmed TB: 22 (85%) on solid culture alone, 2 (8%) on liquid culture alone, and 2 (8%) on both solid and liquid culture. Thirty-four patients received empiric anti-tuberculosis treatment, but only 10 (29%) were culture-positive. Median time to a positive result on solid culture was 92 days (interquartile range [IQR] 69-148) compared to 106 days (IQR 66-157) for liquid culture. No patients initiated treatment following a positive result on liquid culture. The introduction of mycobacterial culture did not influence care for patients undergoing evaluation for TB in Kampala, Uganda. Attention to contextual factors surrounding implementation is needed to ensure the effective introduction of new testing strategies in low-income countries.