International Journal of Microbiology and Immunology Research. Vol. 3(1), pp. 012-018, January, 2014 Available online at http://www.apexjournal.org ISSN 2315-8743© 2014 Apex Journal International Full Length Research Antimicrobial resistance and virulence factors of enterobacteriaceae isolated from food samples of Bangladesh Md. Fakruddin 1 , Md. Mizanur Rahaman 2 , Monzur Morshed Ahmed 1 *, and Mahfuzul Hoque 2 1 Industrial Microbiology Laboratory, Institute of Food Science and Technology (IFST), Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka, Bangladesh. 2 Department of Microbiology, University of Dhaka, Bangladesh. Accepted 23 December, 2013 Enterobacteriaceae (Klebsiella, Enterobacter Shigella, Escherichia and Citrobacter) are pathogens responsible for a wide range of infections. The aim of this study was to determine the antimicrobial resistance and virulence properties of Enterobacteriaceae in food samples of Bangladesh. Fortyfood samples such as milk powder, horlicks, honey, chocolates and biscuits were included. Five genera of Enterobacteriaceae including Shigella, Escherichia, Klebsiella, Enterobacter and Citrobacter were found in 12 among 40 food samples. Among 12 isolates, two Klebsiella, three Enterobacter, three Citrobacter, three Shigella and one Escherichia were identified on the basis of biochemical tests and Carbohydrate utilization assay according to Bergey's Manual of Systematic Bacteriology. These strains were found to have moderately high antibiotic resistance against vancomycin, nitrofurantoin, penicillin G, imipenem, ampicillin adnd neomycin. These isolates can be considered as virulent as they demonstrated many virulence properties. Most of the isolates were capable of producing extracellular protease, curli expression, haemolysin, haemagglutinin, mannose resistant haemagglutinin, had high cell surface hydrophobicity, significant resistance to human serum, can tolerate high concentration of salt and bile. This study concludes that some of the food products in Bangladesh are contaminated with pathogenic Enterobacteriaceae and thus special attention should be given in ensuring hygiene in production and post-processing. Key words: Enterobacteriaceae, food, virulent, Bangladesh. INTRODUCTION Many species of Enterobacteriaceae are members of the normal intestinal flora. A limited number of species, including Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter freundii, Enterobacter aerogenes, Enterobacter cloacae, Citrobacter diversus Shigella boydii, Shigella sonne, Shigella flexneri, Escherichia coli etc. are responsible for a wide range of infections. Enterobacter spp. can be a cause of neonatal meningitis and sepsis (Van Acher et al., 2001). Enterobacter sp. has been isolated from various food products such as mixed *Corresponding author. Email: monzur_29@yahoo.com Tel: +88 01552636715 salad vegetables, meat, milk and cheese (El-Sharoud et al., 2009). Shigella causes dysentery that result in the destruction of the epithelial cells of the intestinal mucosa in the ccecum and rectum. Some strains produce the enterotoxin shiga toxin which causes hemolytic uremic syndrome. The milk products might represent important sources of pathogenic Klebsiella (Gundogan and Yakar, 2007). Muytjens et al. (1988) reported that members of the family Enterobacteriaceae such as Enterobacter agglomerans, Enterobacter cloacae, K. pneumonia, Citrobacter freundii, E. coli, K. oxytoca, C. diversus were isolated most frequently from milk substitute infant formulas. Most species isolated from the powdered substitutes for breast milk have also been mentioned as causes of bacterial meningitis (Muytjens et al., 1988). K.