Survey of Gram Negative and Gram Positive Bacteria in Drinking Water Supplies in Karachi, Pakistan

More than 20,000 children die annually in the city of Karachi alone, majority of whose death are thought to be associated with waterborne pathogens. Drinking water and recreational exposure to polluted water pose a significant public health threat including gastroenteritis, paralysis, meningitis, hepatitis, respiratory illness and diarrhoea. The aim of this study was to determine the presence of bacterial contamination in drinking water supplies in Karachi, Pakistan. A total of fifty two domestic tap water samples were collected from different areas of Karachi, between May to June 2011 and analyzed for bacterial presence based on biochemical testing. The results revealed a high prevalence of Bacillus spp. (86.84%), followed by Pseudomonas spp. (57.14%), Citrobacter spp. (14.28%) Serratia spp., Enterobacteriaceae species (14.28%), Corneybacterium (10.52%), and Acinetobacter spp. (2.63%). These findings disclose bacterial contamination in drinking water supplies, many of which are pathogenic and can produce serious as well as life-threatening infections. Future studies will determine whether bacterial contamination of drinking water occurred post-source contamination. It is recommended that household water treatment interventions should be introduced to improve water quality