Diagnosis of tuberculosis in a high TB-HIV environment using microscopy and culture: The example of Kakiika Prison-Kyamugorani, Mbarara, Uganda

Abstract

There is growing concern about the high transmission of tuberculosis (TB) in prisons posing a risk to the outside community. There are high levels of overcrowding in the Uganda Prisons Service (UPS) with some prisons accommodating 4 times above their designed capacities. Our objective was to determine the prevalence of active pulmonary tuberculosis among prisoners. In addition we assessed the accuracy and reliability of TB smear microscopy using culture as gold standard and determined TB-HIV co-infection. Using a cross-sectional survey, we enrolled 140 male inmates in Kakiika prison-Kyamugorani, Mbarara. TB diagnosis was performed using direct sputum smear microscopy (DSSM) and culture for mycobacteria. HIV results were obtained from the clinical register with consent from the study participants. The prevalence of active pulmonary MTB was 2.9% based on culture findings. Microscopy had no smear positive results. However, there was no evidence that culture is different from microscopy in this sample (P=0.13). The overall HIV prevalence was 15.7% and TB-HIV co-infection was 25%. TB prevalence in this prison was greater than that of other prisons in Uganda at 0.7% and the general opulation at 0.4%. This is because the social and economic conditions that increase vulnerability to TB also increase vulnerability to criminal behavior and imprisonment. In addition, the high TB burden is due to the high HIV prevalence in prisons. The study recommended the use of a more sensitive technique for TB diagnosis specially in settings where the level of transmission is presumed to be high.

Keywords: Culture, Microscopy, Prisons, Tuberculosis, TB/HIV co-infection