*2.2. Identification of Coliforms and Confirmation of E. coli*

Microbiological processing of the samples was started as soon as the samples were received in the laboratory. The samples were processed on selective and differential HiCrome coliform chromogenic agar (HiMedia Laboratories Pvt. Ltd., Mumbai, India) to identify *E. coli* (blue-violet colony) and non-*E. coli* coliforms (*Citrobacter freundii* and *Enterobacter cloacae*—salmon to red, *Klebsiella pneumoniae*—light pink, *Salmonella enteritidis* and *Shigella flexneri*—colorless) as described in detail [9]. The presumptive *E. coli* were confirmed by PCR (mentioned in detail below). Briefly, stool samples were inoculated at 37 ◦C for 24 h directly on the chromogenic agar while the water samples were first filtered through membranes [9], followed by inoculation of the membranes on agar plate. In water samples, colony-forming units (CFUs) per unit volume of sample were estimated for total coliforms and *E. coli* to provide a snapshot of the abundance of coliforms and the *E. coli* load in the samples tested. Six *E. coli* and two colonies from every type of non-*E. coli* were isolated, purified, stored, and processed for antibiotic susceptibility testing and DNA extraction.
