Gross and molecular characterization of Mycobacterium tuberculosis complex in Mekelle town municipal abattoir, northern Ethiopia

A cross-sectional study was conducted from September 2010 to July 2011 on 768 beef cattle in Mekelle town municipal abattoir, northern Ethiopia, to investigate the tuberculoid lesions using a detailed postmortem inspection and characterize its causative agents. Pathological and bacteriological examination and molecular typing were employed to undertake this study. The prevalence of tuberculoid lesions was 6.4% (49/768) with the largest proportion (62.3%) of lesions recorded from the respiratory tract. Exotic breeds (OR=46.6, 95% CI, 8.8-248.3) and female cattle (OR=6.6, 95% CI, 1.7-26.5) were more likely to have tuberculoid lesions. Bacteria were successfully cultured from 59.2% (29/49) tissue; however, using multiplex polymerase chain reaction only four of these isolates showed signal to the genus Mycobacterium of which two were members of the Mycobacterium tuberculosis complex (MTC). The result of this study suggested the importance of MTC and non-Mycobacterium tuberculosis complex (NMTC) in the study area and also revealed that NMTC may contribute for the development of granulomatous lesions in cattle.