ISOLATION, IDENTIFICATION AND ANTIBIOGRAM STUDY OF ESCHERICHIA COLI FROM THE CASES OF MASTITIS

Abstract

The present study was conducted to isolate and identify Escherichia coli from the cases of mastitis in cows at Gaibandha district of Bangladesh. For this, a total of 50 milk samples were collected from clinically & sub-clinically mastitis affected and apparently healthy cows of different dairy farms and rural domestic holdings at Gaibandha district in Bangladesh. The study was carried out during the period from March’2010 to August’2011. The milk samples were collected and brought to the Laboratory under Department of Microbiology, Faculty of Veterinary and Animal Science, Hajee Mohammad Danesh Science and Technology University, Dinajpur and subjected to different bacteriological tests for isolation and identification of bacteria based on morphology, staining, cultural and biochemical examinations. Antibiotic sensitivity of the isolated organisms was also studied. The isolated bacteria were Escherichia coli 30.00 %, Staphylococcus spp. 20.00 %, Streptococcus spp. 20.00 %, Corynebacterium sp. 14.00 % and 16.00 Y%owere unidentified gram positive & gram negative bacteria. On EMB agar Escherichia coli showed greenish black colonies with metallic sheen, On nutrient broth enough whitish turbidity, On MacConkey agar Bright pink colonies were formed. In Gram’s staining technique the Escherichia coli revealed Gram negative, pink color, short rod, cocci, coma, single, pair or in short chain arrangement. Sugar fermentation tests (dextrose, lactose and maltose) were positive and the organism produced acid & gas. In Hanging Drop slide method, the organisms were motile. The organism in another biochemical test showed MR test positive, VP test negative & Indole positive. Results of antibiotic sensitivity of Escherichia coli showed that they were highly sensitive (+++) to Chloramphenicol (70.00 %), Kanamycin (70.00 %) and Nitrofurantoin (90.00 %), moderately sensitive (++) to Erythromycin (50.00 %), Less sensitive (+) to nalidaxic acid (35.00 %), Cephalexin (35.00 %), Amoxycillin (35.00 %) and resistant to Cloxacilin, Ampicillin and Cephradin. The present study dictates that the Escherichia coli was one of the important agents responsible for the mastitis in dairy cows at Gaibandha district of Bangladesh.