Background & aim: The presence, identification, and removal of bacterial pathogens in water and wastewater are the most important health concern. The aim of this study was to identify two important pathotypes of E. coli (enterotoxigenic and enteropathogenic) in hospital, dairy,  slaughterhouse, and municipal wastewater treatment plants of Kermanshah city.

Methods: In this descriptive study, 64 samples were collected from six wastewater treatment plants under sterile and standard conditions and transferred to the microbiology laboratory. E.coli strains were isolated and ETEC and EPEC patotypes were identified using PCR method.

Results: The differential culture results showed E. coli strains in 90.62% of the 64 studied samples. ETEC strains were identified in 42.85, 33.3, 0, 28.6, 0, and 25 %of the influent and in 20, 0, 0, 16.6, 0, and 20% of the effluent samples taken from municipal , Imam Reza hospital, Farabi hospital, dairy plant, Mohammad Kermanshahi hospital, and slaughterhouse wastewater treatment plants, respectively.

Conclusion: The results showed the presence of pathogenic Enterotoxigenic E. coli  in effluent of hospital and municipal  wastewater treatment plants and Enteropathogenic E. coli in slaughterhouse  effluents. Considering the presence of enterotoxigenic patotype in wastewaters, the importance of removing indicator coliform strains in wastewater treatment plants is highlighted. Therefore, serious measures should be taken to improve efficiency of the systems.