Antibiotic Resistance in Shiga Toxigenic Escherichia coli Isolates from Surface Waters and Sediments in a Mixed Use Urban Agricultural Landscape

Urban Farm DB summary

Genomic and phenotypic analysis of 55 Shiga toxin-producing E. coli (STEC) isolates of diverse serotypes, recovered from surface waters and sediments in a mixed urban/agricultural landscape in British Columbia, Canada (Antibiotics, 2021), found reduced antibiotic susceptibility across multiple drug classes: florfenicol (65.5%), tetracycline (52.7%), ampicillin (49.1%), streptomycin (34.5%), amoxicillin/clavulanic acid (21.8%), kanamycin (20.0%), ceftiofur (18.2%), trimethoprim-sulfamethoxazole (12.7%), gentamicin (10.9%), chloramphenicol (7.3%), ceftriaxone (3.6%) and cefoxitin (3.6%), while all isolates remained susceptible to ciprofloxacin, nalidixic acid, ertapenem, imipenem and meropenem. Eight isolates (14.6%) were multidrug resistant, and resistance genes including floR, dfrA, sul1/2, tetA/B, aadA, aph, blaTEM-1b and blaCMY-2 were identified alongside multiple plasmid replicon types. The resistance profiles matched those reported in generic E. coli from food animals, and the authors conclude that aquatic environments in the region are a potential reservoir for the maintenance and transmission of antibiotic-resistant STEC, their resistance genes, and associated plasmids.