Hatha, A A M; Abhirosh, Chandran; Sherin, Varghese; Ellen, Kandeler; Ambattu, Thomas; Asit, Mazumder(Elsevier, January 15, 2011)
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Abstract:
Microcosm studies were performed to evaluate the survival of Escherichia coli, Salmonella paratyphi and
Vibrio parahaemolyticus in water and sediment collected from the freshwater region of Vembanad Lake
(9 35◦N 76 25◦E) along the south west coast of India. All three test microorganisms showed significantly
(p < 0.01) higher survival in sediment compared to overlying water. The survival in different sediment
types with different particle size and organic carbon content revealed that sediment with small particle
size and high organic carbon content could enhance their extended survival (p < 0.05). The results indicate
that sediments of the Lake could act as a reservoir of pathogenic bacteria and exhibit a potential health
hazard from possible resuspension and subsequent ingestion during recreational activities. Therefore,
the assessment of bacterial concentration in freshwater Lake sediments used for contact and non contact
recreation has of considerable significance for the proper assessment of microbial pollution of the
overlying water, and for the management and protection of related health risk at specific recreational
sites. Besides, assessment of the bacterial concentration in sediments can be used as a relatively stable
indicator of long term mean bacterial concentration in the water column above
Description:
International Journal of Hygiene and Environmental Health 214 (2011) 258– 264
Hatha, A A M; Abhirosh, C; Sherin, V; Thomas, A P; Mazumder, A(Elsevier, March 23, 2011)
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Abstract:
To assess the prevalence of faecal coliform bacteria and multiple drug resistance
among Escherichia coli and Salmonella serotypes from Vembanadu Lake.
Study design: Systematic microbiological testing.
Methods: Monthly collection of water samples were made from ten stations on the southern
and northern parts of a salt water regulator constructed in Vembanadu Lake in order to
prevent incursion of seawater during certain periods of the year. Density of faecal colifrom
bacteria was estimated. E. coli and Salmonella were isolated and their different serotypes
were identified. Antibiotic resistance analysis of E. coli and Salmonella serotypes was done
and the MAR index of individual isolates was calculated.
Results: Density of faecal coliform bacteria ranged from mean MPN value 2900 -7100/100ml.
Results showed multiple drug resistance pattern among the bacterial isolates. E. coli
showed more than 50% resistance to amickacin, oxytetracycline, streptomycin, tetracycline
and kanamycin while Salmonella showed high resistance to oxytetracycline, streptomycin,
tetracycline and ampicillin. The MAR indexing of the isolates showed that they
have originated from high risk source such as humans, poultry and dairy cows.
Conclusions: The high density of faecal coliform bacteria and prevalence of multi drug
resistant E. coli and Salmonella serotypes in the lake may pose severe public health risk
through related water borne and food borne outbreaks