Safe drinking water in an urban city has been a great challenge for the human population. Consumption of contaminated water may lead to the occurrence of several diseases. Enterotoxigenic Escherichia coli (ETEC) is an enteric pathogen that can survive even in treated drinking water and cause watery diarrhea. The pathogen harbors virulent and drug-resistant genes responsible for its virulence and antibiotic resistance. Persistence of such strains of ETEC is often associated with disease outbreaks. The present work involves the drug-resistance pattern of ETEC, isolated from drinking water. Zinc Oxide nanoparticles were synthesized using a chemical method and their antimicrobial effects were assessed against drug-resistant strains. In order to increase the antimicrobial efficacy of nanoparticles, guava leaf extracts were used and their synergistic study with Zinc Oxide nanoparticles was carried out. Results showed the prevalence of drug-resistant ETEC in the drinking water of Gwalior city. Our study further indicates the potential antimicrobial activity of Zinc Oxide nanoparticles in synergy with guava leaf extract against ETEC.