Vet World   Vol.11   August-2018  Article-22

An epidemiological investigation on occurrence of enterohemorrhagic Escherichia coli in raw milk

Background and Aim: The aim of the present investigation was to study the epidemiology of enterohemorrhagic Escherichia coli (EHEC) in raw milk and molecular characterization of isolates using multiplex polymerase chain reaction (PCR).

Materials and Methods: A total of 125 raw milk samples were subjected to isolation, identification, and confirmation of virulence-associated genes by multiplex PCR (mPCR). The samples were collected from a milk cooperative society of Thrissur district, Kerala. For further epidemiological investigation, samples such as dung (126), hair coat of cow (60), udder swab (60), udder wash (60), milking utensil wash (36), Milker's hand wash (36), water (36), soil (36), and feed (36) were collected from the households from which the raw milk tested positive for EHEC.

Results: The occurrence of EHEC in individual raw milk samples was found to be 8.8%. The major source of contamination to raw milk was found to be dung (19.84%) followed by udder swab (16.67%), hair coat of cow (15%), Milker's hand and milking utensils and water (11.11% each), and udder wash and soil (8.33% each). For identification of virulence genes, all the isolates were subjected to mPCR, of 75 isolates 73.33% of isolates harbored stx 2 gene while 53.33, 36, and 36% of isolates were encoded by stx 1, eae A, and hly A genes, respectively. On epidemiological survey, the multiple risk factors accountable for occurrence of EHEC in raw milk were found to be the quality of water used, improper and inadequate udder preparation, unhygienic hands of Milker's, use of insufficiently cleaned milking utensils, and using common utensil for washings of udder and milking purposes.

Conclusion: The result of the present study signifies that raw milk was contaminated with EHEC and possesses a high public health threat. As dairy cattle and its environment serve as a potential niche for EHEC, hygienic milking practices should be adopted to curb the occurrence of EHEC in raw milk. Keywords: Enterohemorrhagic Escherichia coli, epidemiological investigation, epidemiological survey, multiplex polymerase chain reaction, raw milk.

Keywords: Enterohemorrhagic Escherichia coli, epidemiological investigation, epidemiological survey, multiplex polymerase chain reaction, raw milk.

How to cite this article: Vanitha HD, Sethulekshmi C, Latha C (2018) An epidemiological investigation on occurrence of enterohemorrhagic Escherichia coli in raw milk, Veterinary World, 11(8): 1164-1170.

Received: 21-02-2018  Accepted: 12-07-2018     Published online: 25-08-2018

Corresponding author: H. D. Vanitha   E-mail: vanivet10@gmail.com

DOI: 10.14202/vetworld.2018.1164-1170

Copyright: Vanitha, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.