Antimicrobial resistance (AMR) is considered a serious problem in many countries, including Thailand. AMR and antibiotic resistance genes (ARGs) could transfer between humans, animals, and the environment causing a threat to human health. This study described the antibiotic resistance of Escherichia coli (E. coli) from surface water, wastewater, and discharge water in the Namsuay watershed in upper northeast Thailand. The water samples were collected in the dry and wet seasons. The 113 E. coli isolates were confirmed using a polymerase chain reaction and examined for their antibiotic susceptibility, ARGs, and genetic relationship. The results indicated that E. coli was resistant to the following classes of antibiotics: fluoroquinolone, third-generation cephalosporin, polymyxin, and carbapenem. The isolates carried the mcr-1, mcr-8, mcr-9, blaoxa-48-like, aac(6')-bl-cr, qepA, and oqxAB genes. Phylogroup B1 was a predominant group among the E. coli in the study. In addition, the E. coli isolates from the discharge water (a hospital and a fish farm) had a higher prevalence of antibiotic resistance and harboured more ARGs than the other water sample sources. The presence of antibiotic-resistant E. coli and ARG contamination in the natural water source reflected an AMR management issue that could drive strategic policy regarding the active surveillance and prevention of AMR contamination.
Keywords: Escherichia coli; Namsuay watershed; PMQR; antibiotic resistance; antimicrobial resistance; carbapenemase; mcr; natural water.