الفهرس 
Title : Bacteriological and molecular studies on Mycobacterium species in cattle
AbstractOnly 14 pages are availabe for public view
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Abstract
In the present study tissue samples showing tuberculous lesions, collected from a total of 153 out of 200 slaughtered positive tuberculin reactors after PM examination, were subjected to bacteriological examination and out of them 83 animals (54.2%) were positive to bTB by microscopic examination of direct smears while by culture on L-J medium, M.bovis was isolated from 100 animals (65.4%). Spleen showed the highest positive results by culture technique at percentage of 68.4% followed by lymph node (66.1%), lung (65.1%) then liver (62.9%). Indirect ELISA, using cocktail antigens, on serum collected from the total 200 reactors detected 28% positive bTB cases. The antibiotic susceptibility testing of 65 isolates, confirmed by conventional PCR targeting Mpb70 as M.bovis, revealed resistance to at least one tested drug in 25 (38.5%) isolates of them 14 isolates were MDR. The overall resistance to tested drugs was 3.1%, 20%, 30.8% and 32.2% for EMB, STR, INH and RIF respectively. For exploring mutations associated with RIF resistance, DNA sequencing was performed on 6 M.bovis isolates and 3 mutations designated as H526Y (4/6), S531L (1/6) and D516V (1/6) were identified. The sequences were submitted to the NCBI GenBank with the accession numbers (OM448574, OM448575, OM448576, OM448577, OM448578 and OM448579). The obtained results emphasise the health hazard of M.bovis and augment the need for further investigation on ante-mortem identification of M.bovis infection in cattle to minimize public risk.