Comprehensive Genome and Plasmidome Analysis of Antimicrobial Resistant Bacteria in Wastewater Treatment Plant Effluent of Tokyo

To characterize environmental antimicrobial resistance (AMR) in urban areas, extended-spectrum beta-lactamase- (ESBL)/carbapenemase-producing bacteria (EPB/CPB, respectively) from urban wastewater treatment plant effluents in Tokyo were isolated on CHROMagar ESBL plate. Complete genome sequence analysis, including plasmids, indicated that 126 CTX-M-positive isolates (31%) were identified among the 404 obtained isolates. The CTX-M-9 group was predominant (n = 65, 52%), followed by the CTX-M-1 group (n = 44, 35%). Comparative genome analysis revealed that CTX-M-27-positive E. coli O16:H5-ST131-fimH41 exhibited a stable genome structure and clonal-global dissemination. Plasmidome network analysis revealed that 304 complete plasmid sequences among 85 isolates were grouped into 14 incompatibility (Inc) network communities (Co1 to Co14). Co10 consisted of primarily IncFIA/IncFIB plasmids harboring bla(CTX-M) in E. coli, whereas Co12 consisted primarily of IncFIA(HI1)/Inc FIB(K) plasmids harboring bla(CTX-M), bla(KPC), and bla(GES) in Klebsiella spp. Co11 was markedly located around Co10 and Co12. Co11 exhibited bla(CTX-M), bla(KPC), and bla(NDM), and was mainly detected in E. coli and Klebsiella spp. from human and animal sources, suggesting a mutual role of Co11 in horizontal gene transfer between E. coli and Klebsiella spp. This comprehensive resistome analysis uncovers the mode of relational transfer among bacterial species, highlighting the potential source of AMR burden on public health in urban communities.

Automated summary

This study characterizes environmental antimicrobial resistance (AMR) in urban areas by analyzing wastewater samples from urban wastewater treatment plants in Tokyo. The findings reveal the presence of extended-spectrum beta-lactamase- (ESBL)/carbapenemase-producing bacteria and their genetic characteristics. The study highlights the potential source of AMR burden on public health in urban communities.