Bacteriological and Molecular studies on Mycobacterium Bovis in Cattle, with Special Reference to its Antimicrobial Resistance

Abstract

In current study a total of 153 tuberculous lesion samples collected from cattle after PM examination (69 from El-Menufia, 47 from El-Sharkia and 37 from El-Qaliobia governorates) were subjected to bacteriological examination. Eighty-three samples showed the AF bacilli in direct smears stained by ZN stain at a percentage of 54.2% while by the culture method, M. bovis was isolated from 100 (65.4%) samples. Sixty-five isolates, confirmed to be M. bovis by conventional PCR targeting Mpb70, were tested for the sensitivity to anti-tuberculous drugs and 25 isolates showed resistance to at least one tested drug. The overall resistance to EMB was 3.1% and resistance to STR, INH and RIF were 20, 30.8 and 32.3% respectively. MDR was detected in 14 (21.5%) isolates. For DNA sequencing, PCR targeting rpoB gene, conferring rifampicin resistance, was performed on selected 6 isolates and identified three mutations designated as H526Y (4/6), S531L (1/6) and D516V (1/6) and the sequences were submitted to the NCBI GenBank with the accession numbers (OM448574, OM448575, OM448576, OM448577, OM448578 and OM448579). The obtained results are epidemiologically significant and augment the necessity of further investigation on ante-mortem identification of M. bovis infection in cattle to minimize public risk.