MOLECULAR CHARACTERIZATION OF E. COLI ISOLATED FROM RAW MILK A THESIS BY MOST. SHAHINUR AKTER

Abstract

The present study was conducted to isolate and identify Escherichia coli from raw milk at Rangpur division of Bangladesh. For this, a total of 60 milk samples were collected from different dairy farms and rural domestic holdings at Rangpur division in Bangladesh. The study was carried out during the period from July, 2017- May, 2018. 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. Molecular test using PCR was also studied. The isolated bacteria were Escherichia coli 30.00%, Staphycoccus spp. 20%, Salmonella spp 20%, Corynebacterium spp. 16%. On nutrient broth enough whitish turbidity, On MacConkey agar Bright pink colonies were formed and On EMB agar Escherichia coil showed greenish black colonies with metallic sheen. In Gram’s staining technique the Escherichia coil revealed Gram negative, pink color, short rod, cocci, coma, single, pair or in short chain arrangement. The organism in biochemical test viii showed MR test positive, VP test negative & Indole positive. In statistical analysis, the prevalence of the isolates in different dairy farm found from this study was non-significant. Present study indicates that the Escherichia coli was one of the important bacteria that available in raw milk of the sample collection area at Rangpur district of Bangladesh.