ISOLATION AND CHARACTERIZATION OF ESCHERICHIA COLI FROM THE CASES OF COLIBACILLOSIS IN CALF

Abstract

The study was conducted for the isolation, identification and antibiogram study of E. coli from different places of Dinajpur Sadar Upazilla. The study was performed by using cultural, biochemical and antibiogram study. Out of 140 clocal samples collected from calves.Among this 84 sample was collected from diarrheic calves.From these sample 30 samples was positive. Sample was also collected from the 56 apparently healthy calves.Among these 13 was found positive. It was found that the prevalence of E.coli was higher in diarrhoeic calves (35.71%) compared with apparently healthy (23.21%) calves were found to be positive for E. coli infection. During cultural examination, all positive isolates produce turbidity on nutrient broth, circular smooth colored colony on nutrient agar; Slight pinkish smooth colony on SS agar; hemolysis on blood agar; bright pink color colony on MacConkey’s agar and characteristic metallic sheen on EMB agar. The positive isolates produce acid and gas by fermenting various sugars (Glucose, Fructose and Maltose) and gave positive reaction to Indole, Methyl red test but negative reaction to Voges Proskeur and citrate utilization test. The antibiotic sensitivity pattern showed that E. coli isolates were moderate sensitive to ciprofloxacin, chloramphenical, gentamicin and cephalexin, less sensitive to kanamycin and cephradine and resistant to amoxycillin, streptomycin, tetracycline and nalidixic acid.