Molecular Detection of Enrofloxacin Resistant genes in Escherichia coli Isolates from Broiler in Tehran and Tonekabon

E.coli is one of the most prevalent pathogenic factor in poultry which causes colibacillosis. This disease is responsible for lots of economic losses that happen for poultry industry all around the world. Fluoroquinolones especially enrofloxacin is widely used as treatment for the disease in poultry farms. Having anomalous and vast usage of fluoroquinolones in poultry industry would increase antibiotic resistance risk inpathogenic E.coli. DNA gyrase (topoisomerase II) and topoisomerase IV are the main targets for fluoroquinolones. Mutation in encoding genes of DNA gyrase and topoisomerase can be considered as the main cause in resistance to fluoroquinolones in E. coli. The objective of the present study was to identify associated mutation interfering genes to enrofloxacin. Among 80 genera of E.coli there were recognized just 20 through diffusion disk method resistant against enrofloxacin. Then we considered the existence of mutants in genes:gyrA, gyrB, parC and parE. Some mutations like D87→N, S83→L were recognized in gyrA also F514→S in gyrB, S80 →I in parC but no mutation that leading to exchange was seen in parE.