The Emergence of blaNDM-Encoding Plasmids in Enterobacteriaceae Isolated from Shared Water Resources for Livestock and Human Utilization in Central Thailand

Abstract

Background/Objectives: The environmental dissemination of antimicrobial-resistant Enterobacteriaceae poses a remarkable threat to public health. This study investigates the environmental presence and dissemination of carbapenemase-producing Enterobacteriaceae (CPE) in 30 important water bodies selected according to their interconnection with and utilization by livestock and community people in central Thailand. Methods: Water samples were collected from 30 selected water bodies. Enterobacteriaceae were isolated and screened for CPE and multidrug resistance. Carbapenemase genes (bla<inf>NDM-5</inf>, bla<inf>NDM-1</inf> and bla<inf>IMI-1</inf>) were detected and their locations (plasmid and chromosome) determined. Plasmid types were further characterized, and conjugation experiments were performed to assess transferability among bacterial species. Results: From all selected samples, six isolates (20%) were identified as multidrug-resistant CPE including one Escherichia coli, one Klebsiella pneumoniae and four Enterobacter roggenkampii carrying bla<inf>NDM-5</inf>, bla<inf>NDM-1</inf> and bla<inf>IMI-1</inf> genes, respectively. The bla<inf>NDM-5</inf> and bla<inf>NDM-1</inf> genes were located on phage-like pO111 type plasmid and IncC plasmid, while bla<inf>IMI-1</inf> was located on chromosomes. The plasmids also consisted of components that closely resembled those found in resistance plasmids obtained from clinical and environmental isolates worldwide. Additionally, through plasmid conjugation experiment, carbapenemase genes were transferable with a high rate among bacterial species. Conclusions: These findings indicated that water bodies are polluted and there is an urgent need for integrated strategies to monitor and mitigate the spread of antibiotic resistance across human, animal and environmental health domains in aquatic environments.