الفهرس 
ContentsOnly 14 pages are availabe for public view
 |  | from | 107 |  |  |
| | | from | 107 | | |
Abstract
In this study, total of 232 samples from cow and calves (155 milk samples from mastitic cow, 73 nasal swabs from pneumonic calves and 4 vaginal swabs from metritic cow) were examined by conventional methods. Among these samples, 39 samples were confirmed to be E. coli positive. Recovered isolates were then assayed for virulence genes by using polymerase chain reaction (PCR). Phenotypically most clinical isolates of E. coli which were found to be resistant to antibiotic classes were selected and further studied to see its various resistance mechanisms genotypically by using polymerase chain reaction. Recovered E. coli isolates were assayed for virulence genes by polymerase chain reaction (PCR). Our result revealed that 13.1% of E. coli isolates carried iroN and 10.5 % of E. coli isolates carried iss gene. E. coli isolates were assayed for presence of integron and resistance genes by polymerase chain reaction (PCR). Our result revealed that 13.1% carried integron that responsible for capture of antibiotic resistance genes and transferred them among bacteria, 18.4% carried blaTEM and blaSHV genes, (50%) were carrying dhfrIa, 10% carrying sulI and 70% carrying sulII, 80% carrying aphA1gene.These genes responsible for B- lactams, Trimethoprim-sulphamethazole and kanamycin resistance respectively. In conclusion, naturally, increased virulence may evolve in response to increased antimicrobial resistance. So we must control the spread of virulence, also as the control of antimicrobial resistance spread. The intensive use of antibiotics would increase the number of antibiotic resistance and integron prevalence which could be a significant public health importance and can transfer antibiotic resistance genes to other bacteria and the E. coli in this study can be considered a reservoir of resistance genes and highlight the need for the abundant use of antimicrobials in animal husbandry.