ISOLATION AND IDENTIFICATION OF CORYNEBACTERIUM SP. FROM THE CASES OF CLINICAL MASTITIS IN COW AT DINAJPUR DISTRICT OF BANGLADESH

Abstract

The present study was conducted to isolate and identify Corynebacterium sp. from the cases of clinical mastitis in cows at Dinajpur district of Bangladesh. For this, a total of 20 milk samples were collected from clinically mastitis affected cows of different dairy farms and rural domestic holdings at Dinajpur district in Bangladesh. The study was carried out during the period of September’2010 to February’2011. The milk samples were collected and brought to the 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 properties. Antibiotic sensitivity of the isolated organism was also studied. The isolated bacteria were Staphylococcus spp. (25%), Streptococcus spp. (15%), Escherichia coli (20%), Corynebacterium sp. (25%) and 15% were unidentified. On nutrient broth, the Corynebacterium sp. showed enough whitish turbidity and on nutrient agar the colonies were grayish in color while on blood agar the colonies were grayish in color about 1mm in diameter and surrounded by a small zone of hemolysis. In Gram’s staining technique the Corynebacterium sp. revealed Gram positive, violet color, short cocco-bacilli and arranged in bundles or clusters and singly also. In sugar fermentation tests (dextrose, lactose and maltose), the organism produced acid but no gas. In hanging drop slide method, the organism was nonmotile. Results of antibiotic sensitivity showed that Corynebacterium sp. was highly sensitive to gentamicin and ciprofloxacin, and some degree of resistance to tetracycline, ampicillin, penicillin and amoxycillin. The present study dictates that the Corynebacterium sp. was one of the important agents responsible for the clinical mastitis in cows at Dinajpur district of Bangladesh.