Antimicrobial-ResistantEscherichia Colifrom Environmental Waters in Northern Colorado

WaterborneEscherichia coliare a major reservoir of antimicrobial resistance (AMR), including but not limited to extended-spectrum beta-lactamase (ESBL) andKlebsiella pneumoniaecarbapenemase (KPC) mechanisms. This study quantified and described ESBL- and KPC-producingE. coliin Northern Colorado from sewer water, surface water, and influent and effluent wastewater treatment sources. Total detected bacteria andE. coliabundances, and the percentages that contain ESBL and/or KPC, were compared between water sources. SeventyE. coliisolates from the various waters had drug resistance validated with a panel of 17 antibiotics using a broth microdilution assay. The diverse drug resistance observed acrossE. coliisolates was further documented by polymerase chain reaction of common ESBL genes and functional relatedness by PhenePlate assay-generated dendrograms (n=70). The totalE. coliabundance decreased through the water treatment process as expected, yet the percentages ofE. coliharboring ESBL resistance were increased (1.70%) in surface water. Whole-genome sequencing analysis was completed for 185 AMR genes in wastewaterE. coliisolates and confirmed the presence of diverse AMR gene classes (e.g., beta-lactams and efflux pumps) in isolate genomes. This study completed surveillance of AMR patterns inE. colithat reside in environmental water systems and suggests a role for integrating both phenotypic and genotypic profiling beyond ESBL and KPC mechanisms. AMR screening via multiple approaches may assist in the prevention of drug-resistantE. colispread from waters to animals and humans.