Pathogenic bacteria and their antibiotic resistance profile in irrigation water in farms from Mexico

The presence of antibiotic-resistant bacteria in the agro-environment is a growing international concern. In Mexico, few studies thus far have assessed the quality of water irrigation through the isolation of bacteria pathogens and the identification of antibiotic-resistant genes. Irrigation water samples obtained from rivers, wells, and ponds in different regions of Mexico were analyzed for the presence and antibiotic resistance of pathotypes of Escherichia coli, Salmonella spp., and Enterococcus spp. using selective agars and polymerase chain reaction. Two Enterococcus faecalis, one typical enteropathogenic (EPEC), and one atypical EPEC pathotypes were isolated from river water samples; two atypical EPEC and one enterotoxigenic pathotypes were isolated from pond water samples. There were no targeted pathogens detected in well water samples. All isolates were resistant to at least three antibiotics, with vancomycin being the most common; however, all isolates were sensitive to trimethoprim and ciprofloxacin. The presence of pathotypes of EPEC and ETEC and E. faecalis in water samples used for crop irrigation are a potential risk to public health because of their pathogenicity and antibiotic resistance.