Tracking environmental antimicrobial resistance: Isolation and antimicrobial susceptibility patterns of E. coli across hospital, livestock, and community settings in Gampaha, Sri Lanka.

The emergence and spread of antimicrobial resistance (AMR) are multifactorial, necessitating a One Health approach for its mitigation. Indiscriminate and unnecessary antimicrobial use drives AMR within hospitals and livestock farms, hypothesized as key hotspots. This descriptive cross-sectional study was carried out to investigate environmental contamination by non-susceptible Escherichia coli (E. coli) in hospitals, livestock farms, and a community in close proximity to a hospital in the Gampaha District, Sri Lanka. A total of 134 environmental samples were collected, comprising wastewater (n = 74), soil (n = 30), and groundwater (n = 30). Of these, 54 samples were obtained from five hospitals, 50 samples from six livestock farms, and 30 groundwater samples from the surrounding community. A total of 49 (36.56%) E. coli isolates were recovered (hospitals = 15/54, 27.77%, livestock farms = 31/50, 62%, community = 3/30, 10%). Of the total, 27 (55.1%) isolates (hospitals = 11/15, 73.33%, livestock farms = 16/31, 51.61%, community = 0) were non-susceptible to at least 1 of 7 antibiotics tested. Highest rate of non-susceptibility was observed for ampicillin (24/49, 48.97%), followed by co-trimoxazole (16/49, 32.65%), ciprofloxacin (13/49, 26.53%), co-amoxiclav (9/49, 18.36%), cefotaxime (7/49, 14.28%), gentamicin (2/49, 4.08%), and meropenem (1/49, 2.04%). Of the total isolates, 16.32% (8/49) were multidrug-resistant (MDR). These findings demonstrate that hospital and livestock environments may act as important reservoirs of AMR E. coli, underscoring the urgent need to integrate environmental surveillance, wastewater management, and antimicrobial stewardship into Sri Lanka's One Health AMR control strategies.