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Abstract:
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In the present study diversity of E. coli in the water samples of Cochin
estuary were studied for a period of 3 years ranging from January 2010-
December 2012. The stations were selected based on the closeness to satellite
townships and waste input. Two of the stations (Chitoor and Thevara) were
fixed upstream, two in the central part of the estuary namely Bolgatty and Off
Marine Science Jetty, and one at the Barmouth. Diversity was assessed in
terms of serotypes, phylogenetic groups and genotypes. Two groups of
seafood samples such as fish and shellfish collected from the Cochin estuary
were used for isolation of E. coli. One hundred clinical E. coli isolates were
collected from one public health centre, one hospital and five medical labs in
and around Cochin City, Kerala. From our results it was clear that pathogen cycling is occurring through
food, water and clinical sources. Pathogen cycling through food is very
common and fish and shellfish that harbour these strains might pose potential
health risk to consumer. Estuarine environment is a melting pot for various
kinds of wastes, both organic and inorganic. Mixing up of waste water from
various sources such as domestic, industries, hospitals and sewage released
into these water bodies resulting in the co-existence of E. coli from various
sources thus offering a conducive environment for horizontal gene transfer. Opportunistic pathogens might acquire genes for drug resistance and virulence
turning them to potential pathogens. Prevalence of ExPEC in the Cochin
estuary, pose threat to people who use this water for fishing and recreation.
Food chain also plays an important role in the transit of virulence genes from
the environments to the human. Antibiotic resistant E. coli are widespread in
estuarine water, seafood and clinical samples, for reasons well known such as
indiscriminate use of antibiotics in animal production systems, aquaculture
and human medicine. Since the waste water from these sources entering the
estuary provides selection pressure to drug resistant mutants in the
environment. It is high time that the authorities concerned should put systems
in place for monitoring and enforcement to curb such activities. Microbial
contamination can limit people’s enjoyment of coastal waters for contact
recreation or shellfish-gathering. E. coli can make people sick if they are
present in high levels in water used for contact recreation or shellfish gathering.
When feeding, shellfish can filter large volumes of seawater, so
any microorganisms present in the water become accumulated and
concentrated in the shellfish flesh. If E. coli contaminated shellfish are
consumed the impact to human health includes gastroenteritis, urinary tract
infections (UTIs), and bacteraemia. In conclusion, the high prevalence of various pathogenic serotypes and
phylogenetic groups, multidrug-resistance, and virulence factor genes detected
among E. coli isolates from stations close to Cochin city is a matter of
concern, since there is a large reservoir of antibiotic resistance genes and
virulence traits within the community, and that the resistance genes and
plasmid-encoded genes for virulence were easily transferable to other strains.
Given the severity of the clinical manifestations of the disease in humans and the inability and/or the potential risks of antibiotic administration for
treatment, it appears that the most direct and effective measure towards
prevention of STEC and ExPEC infections in humans and ensuring public
health may be considered as a priority. |