UC Berkeley

Although access to piped drinking water continues to increase globally, information on the prevalence and clonal composition of coliforms found in piped water systems in low-resource settings remains limited. From June to July 2016, we examined Escherichia coli isolates in domestic water from the distribution system in Alibag, a small town in India. We analyzed the isolates for drug resistance and genotyped them by multilocus sequence typing. Of 147 water samples, 51 contained coliforms, and 19 (37%) of the 51 were biochemically confirmed to contain E. coli. These samples contained 104 E. coli isolates-all resistant to ampicillin. Resistance to ceftazidime was observed in 52 (50%) isolates, cefotaxime in 59 (57%), sulfamethoxazole-trimethoprim in 46 (44%), ciprofloxacin in 30 (29%), and gentamicin in two (2%). Thirty-eight (36%) belonged to sequence types recognized as extraintestinal pathogenic E. coli (ExPEC); 19 (50%) of these 38 ExPEC belonged to known uropathogenic E. coli lineages. This exploratory field research shows the extent to which "improved" drinking water is a potential source of E. coli strains capable of causing extraintestinal infections.