Enumeration of Escherichia coli in Selected Rural Ground Water Supplies in Andhra Pradesh

In developing countries, a variety of alternative methods have been developed and evaluated, but to date all have exhibited limitations andinaccuracies in their enumeration of E. coli in natural water resources. If the microbial contamination of these water sources continues to worsen it would mean a severe human health risk, especially to those individuals using these water sources for drinking, washing and recreational purposes. To this end, we investigated the levels of Escherichia coli in the ground water sources collected from 9 rural areas in Andhra Pradesh as E.coli is the best indicator of fecal contamination. Two most probable number methods-MUG with Escherichia coli and A-1 broth incubation were compared for the enumeration of E.coli-in water The addition of 4-methylumbelliferyl-â-D-glucuronide to the E. coli broth step enabled the direct enumeration of E. coli instead of fecal coliforms. We observed that E.coli numbers were significantly higher using the A-1 procedure in the collected ground water samples. We had investigated this observation using geometric mean analysis to compare the two methods and evaluated the applicability of the A-1 procedure to water analysis in rural areas. A-1 procedure was found to be the method of choice for health related monitoring of the microbial water quality in water sources.