Virulence genes, serobiotypes and antibiotic resistance profile of Escherichia coli strains isolated from aquaculture and other sources
Virulence genes, serobiotypes and antibiotic resistance profile of Escherichia coli strains isolated from aquaculture and other sources
Date
2010
Authors
Surendraraj, A.
Thampuran, N.
Joseph, T.C.
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
In order to determine the prevalence of pathogenic
Escherichia coli, a total number of 155 E. coli isolates
from aquaculture, clinical and veterinary sources
were screened for seven pathogenic virulence markers
and a house-keeping gene by a polymerase
chain reaction. The targeted virulence genes included
eaeA of enteropathogenic E. coli, elt and est of
enterotoxigenic E. coli (ETEC), ipaH of enteroinvasive
E. coli, pCVD432 of enteroaggregative E. coli, stx, hlyA
and eaeA of shigatoxigenic E. coli (STEC) and Enterohaemorrhagic
E. coli. All the isolates were positive for
phoA, the house-keeping gene for E. coli. Among the
155 isolates, seven numbers (4.5%) harboured the
virulencemarkers belonging to the pathogenic group
ETEC and STEC. The virulent genes detected in these
groups were elt, est, hlyAand stx.The sources of these
virulence genes were ¢sh (hlyA), shrimp (elt), feeder
canal water (hlyA and elt) of aquaculture origin and
from diarrhoea a¡ected cow (hlyA, est and stx). The
isolates with pathogenic traits belonged to the serogroups
O6 or O29 and the remaining could not be
typed. They showed resistance to two to four antibiotics
out of the 12 antibiotics tested. Biotyping revealed
that three isolates belonged to a single
biotype (7333) and the remaining isolates were of diverse
types. In conclusion, a molecular tool such as
PCR proves as more e¡ective tool for detection of this
pathogen than the conventional methods. Detection
of these emerging pathogens in aquaculture samples
warrants for strict adherence to hygienic handling at
retail outlets and proper cooking by the consumer before consumption
Description
Keywords
E. coli, aquaculture farms, virulence marker, PCR
Citation
Aquaculture Research 2010, 41: 1003-1014