Asian Australas. J. Biosci. Biotechnol. 2016, 1 (1), 31-36 Asian-Australasian Journal of Bioscience and Biotechnology ISSN 2414-1283 (Print) 2414-6293 (Online) www.ebupress.com/journal/aajbb Article Characterization of diarrheagenic Escherichia coli isolated from pig in Dinajpur, Bangladesh Md. Mahmudul Hasan 1 , Md. Mostafizer Rahman 1 , Mirza Mienur Meher 2 , Mohummad Muklesur Rahman 3 and AKM Mostafa Anower 2* 1 Department of Microbiology, Faculty of Veterinary and Animal Science, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh 2 Department of Microbiology and Public Health, Faculty of Animal Science and Veterinary Medicine, Patuakhali Science and Technology University, Patuakhali, Bangladesh 3 Veterinary Surgeon, District Veterinary Hospital, Gazipur, Bangladesh *Corresponding author: Dr. AKM Mostafa Anower, Department of Microbiology and Public Health, Faculty of Animal Science and Veterinary Medicine, Patuakhali Science and Technology University, Patuakhali, Bangladesh. Mobile: +88 01711069468; E-mail: anower@pstu.ac.bd Received: 03 March 2016/Accepted: 04 April 2016/ Published: 30 April 2016 Abstract: Pig diarrhea is a common problem in pig farms and scattered areas of Bangladesh. This study was subjected to characterize Escherichia coli isolated from fecal sample of pig diarrhea and to find out therapeutic possibilities in the treatment of the disease. Isolation and characterization of the microorganisms were confirmed on the basis of their morphology, staining, cultural and biochemical properties. The study was conducted on 125 fecal samples of diarrheic pig. The prevalence of E. coli infection was higher in 2 years and above aged pigs (62.50 %). Prevalence of E. coli was higher in diarrheic pigs 61.00 % (100) and non diarrheic 32.00% (25) were also found to be positive for E. coli. The results of MR and Indole test of E. coli isolates were positive. The antibiogram study revealed that this isolates were highly sensitive to ciprofloxacin, levofloxacin and gentamicin; moderately sensitive to colistin sulphate and azithromycin; less sensitive to amoxicillin, tetracycline, cloxacillin, ceftraexon, neomycin, erythromycin and ampicillin. The findinings of the experiment indicates that the use of ciprofloxacin, levofloxacin and gentamicin may have the preference to be choice in clinical control of E. coli causing pig diarrhea. Keywords: antimicrobial agents; Escherichia coli; isolation; characterization; pig diarrhea 1. Introduction Diarrhea is one of the most likely reasons in young and aged pigs become sick or dies. Pig diarrhea is a complex disease, with many interrelated causes, agent, host and environmental factors collectively explain diarrhea and these factors interact dynamically over the course of time (Smith, 2007). The first week of life is a critical period for the newborn piglets and is generally associated with a mortality rate of 10%. Diarrhea is one of the major causes of mortality in newborn piglets, the incidence of diarrhea in pig under one year ranges between 15 to 20%, the greatest risk occurring during the first two weeks of life (Adesiyun et al., 2001). Young pig diarrhea is a multifactorial disease which despite decades of research on the topi born alive in 2002, and diarrheic remains the most common cause of death of pig. The overall mortality in preweaned piglets was 10.5% and diarrhea accounted for 62.1% of pig losses (Lorenz, 2006). In Bangladesh, pig diarrhea remains the most often reported clinical problem in pig management and rearing system (Debnath et al., 1990). Prevalence of Escherichia coli in fecal samples was higher in yearling pig than in cull pigs (Van Donkersgoed et al., 2005). There are not less than forty diseases or manifestations which cause diarrhea in pig. The agents responsible for most pig diarrhea are mainly bacteria, viruses, fungi, protozoa,