Molecular Epidemiology of Nontyphoidal Salmonella in Poultry and Poultry Products in India: Implications for Human Health
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Date
2015-04
Journal Title
Journal ISSN
Volume Title
Publisher
Springer
Abstract
Human infections with non-typhoidal Salmonella
(NTS) serovars are increasingly becoming a threat
to human health globally. While all motile Salmonellae
have zoonotic potential, Salmonella Enteritidis and Salmonella
Typhimurium are most commonly associated with
human disease, for which poultry are a major source. Despite
the increasing number of human NTS infections, the
epidemiology of NTS in poultry in India has not been fully
understood. Hence, as a first step, we carried out epidemiological
analysis to establish the incidence of NTS in
poultry to evaluate the risk to human health. A total of
1215 samples (including poultry meat, tissues, egg and
environmental samples) were collected from 154 commercial
layer farms from southern India and screened for
NTS. Following identification by cultural and biochemical
methods, Salmonella isolates were further characterized by
multiplex PCR, allele-specific PCR, enterobacterial repetitive
intergenic consensus (ERIC) PCR and pulse field gel
electrophoresis (PFGE). In the present study, 21/1215
(1.73 %) samples tested positive for NTS. We found
12/392 (3.06 %) of tissue samples, 7/460 (1.52 %) of
poultry products, and 2/363 (0.55 %) of environmental
samples tested positive for NTS. All the Salmonella isolates
were resistant to oxytetracycline, which is routinely
used as poultry feed additive. The multiplex PCR results
allowed 16/21 isolates to be classified as S. Typhimurium,
and five isolates as S. Enteritidis. Of the five S. Enteritidis
isolates, four were identified as group D Salmonella by
allele-specific PCR. All of the isolates produced different
banding patterns in ERIC PCR. Of the thirteen macro restriction
profiles (MRPs) obtained by PFGE, MRP 6 was
predominant which included 6 (21 %) isolates. In conclusion,
the findings of the study revealed higher incidence of
contamination of NTS Salmonella in poultry tissue and
animal protein sources used for poultry. The results of the
study warrants further investigation on different type of
animal feed sources, food market chains, processing plants,
live bird markets etc., to evaluate the risk factors, transmission
and effective control measures of human Salmonella
infection from poultry products.
Description
TNV_IJM_2015_55(3)319-326
Keywords
Veterinary Science