Abstract: The study of cows Mycobacterium tuberculosis rpoB and katG gene mutations and the relation between drug resistance. Take 30 strains of clinical isolates of M.tuberculosis from cattle, use of phage amplified biologically assay on the drug sensitivity of Rifampicin and isoniazid, polymerase chain reaction-DNA direct sequencing rpoB and katG gene were amplified and sequenced, analysis of rpoB and katG gene mutations and drug resistance associate. The results showed that 15 resistant strains in four were resistant to RFP, three of them found mutations at condon 531 occurred in 75.00%（3/4); 9 single INH-resistant strains of seven mutations,6 isolates mutation at condon 315 occurred in 85.71%(6/7), 1 isolate mutation at condon 463 occurred in 14.29%（1/7）; 2 isolates were resistant to RFP and INH, sequencing showed that two were both mutations at condon 531 in the rpoB gene and condon 315 in the katG gene. All strains were not found the deletion of rpoB and katG gene. The main mechanism of RFP and INH drug resistance is mutations at condon 531 in the rpoB gene and condon 315 in the katG gene; while detection of bovine tuberculosis RFP-resistance, it can be initial screening MDR M.tuberculosis.

Key words: Mycobacterium tuberculosis; Rifampicin; isoniazide; rpoB; katG; multi-drug resistant