Genotyping of mycobacterium tuberculosis isolated from pulmonary tuberculosis patients among people living with HIV in Addis Ababa: Cross-sectional study

Abstract

BackgroundTuberculosis is a serious infection that is common in people living with HIV and increases the mortality and morbidity from the diseases. The study of genetic diversity among strains of M. tuberculosis has a great impact in studying pathogenicity and transmissibility, design for vaccines production, identification of nominee genes for drug targets, and improving molecular diagnostic techniques. The aim of this study was to characterize Mycobacterium tuberculosis (Mtb) isolated from suspected pulmonary tuberculosis among people living with HIV. MethodA total of 143 sputum samples was collected and transported to Akililu Lemma TB laboratory. The collected samples were processed for culture using Lowenstein-Jensen medium. For 45 culture positive isolates, genotyping of mycobacterial DNA was performed by spoligotyping and isolates were assigned to families using the SpolDB4 and the model-based program ‘SPOTCLUST’. Categorical data were analyzed by Chi-square test. ResultA high level of diversity was found among the 45 isolates. Twenty six different Spoligo patterns were obtained. The T (46.7%), Family33 (44.4%) and Central Asian (CAS): (4.4%) families were the dominant isolates comprising 91.5% of the total strains. Of 44% of the Euro-American, 6/20(30%) and 9/20(45%), identified were lineage belonged to Spoligo-International-Type (SIT336) and SIT149. Of the total strains, 12 (22%) were unique and have not been described in SpolDB4 to date. ConclusionWe found the high diversity of Mtb in pulmonary tuberculosis patients in this setting. T3_ETH family identified as the numerous M.tuberculosis strains circulating in the community.