Determining the antibacterial resistance pattern of Escherichia coli isolated from poultry infected with colibacillosis in Kohgiluyeh and Boyer-Ahmad province of Iran

One hundred and fifty samples suspected of coli bacillosis were isolated from broilers; laying hens and mother hens were sampled from 21 farms. The test was positive in 98 cases. And their sensitivity to ten types of antibiotics was investigated using antibiogram method, the disc diffusion method and the growth inhibition halo diameter in (mm). Ninety positive cases (60%) were meat breeding chickens and 8 positive cases (5.33%) were mother and laying hens. The antibiotic discs were related to tetracycline, ampicillin, difloxacin, enrofloxacin, doxycycline, sulfamethoxazole + trimethoprim, ciprofloxacin, calcitin, florfenicol, Fozbak. The biggest halo was related to florfenicol and Fosbak (21-22 mm). Also, the smallest halo was related to tetracycline and ampicillin (8-9 mm). Average halo diameter among ten antibiotics was measured from less than 8 mm to more than 22 mm. . All isolated Escherichia coli were at least 26% resistant to 7 types of antibiotics. Old generation antibiotics such as tetracycline and ampicillin were less effective than new generation antibiotics. In conclusion, the frequency of antibacterial resistance was high due to their excessive consumption and it would be a serious risk for the country's poultry industry and public health.