Prevalence and molecular identification of Mycobacteria isolated from animals slaughtered at Sokoto modern abattoir, Sokoto State, Nigeria

This study investigated the molecular epidemiology of Mycobacteria isolated from animals slaughtered at Sokoto modern abattoir. During meat inspection, 104 suspected tuberculosis lesions were sampled from a total of 102,681 animals slaughtered between November 2016 and January 2018. These samples were subjected to Ziehl Neelsen staining, followed by culture on Lowenstein-Jensen media. Subsequently, polymerase chain reaction (PCR) and sequencing of the 65KDa heat shock protein (hsp65) gene were performed to identify and phylogenetically characterize the cultured organisms. Because sequencing of the hsp65 gene was unable to distinguish between Mycobacterium bovis (M. bovis) and M. tuberculosis, PCR was performed to amplify a genomic region-specific to M. bovis in order to differentiate them from M. tuberculosis. Results showed that, 14 samples yielded growth after culture. Furthermore, hsp65 was detected in 9 out of the 14 isolates screened, 5 of the amplicons were successfully sequenced. Similarity search using NCBI BLAST tool showed the five sequences to share highest identities with Mycobacterium novocastrense (95.99%), M. canettii (94.54%), and M. tuberculosis/M. bovis (100%). Two out of the 5 isolates were confirmed to be M. bovis after PCR amplification using M. bovis specific primers. Phylogenetic tree further confirmed the identity of these isolates by placing them close to species of their kind. Further studies should be conducted to establish the transmission dynamics of the zoonotic Mycobacteria between animals and their owners, to facilitate control and eradication of tuberculosis.