RISK ASSESSMENT OF WATER SOURCES FOR PATHOGENIC Escherichia coli
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Date
2021-04-26
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Sher-e-Kashmir University of Agricultural Sciences & Technology, Jammu (J&K)
Abstract
The present study assessed the water sources for Escherichia coli and pathogenic strains of E. coli viz., ETEC, EHEC and EPEC. A total of 141 water samples (43 river, 28 pond, 10 lake, 40 municipal supply and 20 wells) were analyzed. The isolation strategy involved MacConkey agar supplemented with MUG to identify colonies having β-glucuronidase and lactose fermentation activity. Phenotypically identified E.coli isolates were also confirmed by PCR for YaiO gene. E. coli isolates were analyzed by PCR for ETEC, EHEC and EPEC. From 81 natural water sources, 56 samples (27 river, 20 pond and 9 lake samples) were positive for E. coli and 146 E. coli isolates were obtained. None of 146 isolates was positive for lt, stIa, stIb and eaeA genes while 5 isolates (3 from river samples and 2 from pond samples) were positive for stx1 and 1 isolate was positive for stx2. From 60 samples collected from sources intended for human drinking, 15 samples (13 municipal supply and 2 wells) were positive for E. coli and 43 E. coli isolates were obtained. None of 43 isolates was positive for lt, stIa, stIb and eaeA, stx1 and stx2 genes. The study tried to achieve real-time monitoring of water sources for faecal contamination by isolating E. coli. The geo-referencing of sampling sites was done so that positive sites especially municipal supply could be explored further to check the areas where faecal contamination is occurring.