<p>Characterization of NDM-5- and CTX-M-55-coproducing <em>Escherichia coli</em> GSH8M-2 isolated from the effluent of a wastewater treatment plant in Tokyo Bay</p>

Abstract

Purpose New Delhi metallo-β-lactamase (NDM)-5-producing Enterobacteriaceae have been detected in rivers, sewage, and effluents from wastewater treatment plants (WWTPs). Environmental contamination due to discharged effluents is of particular concern as NDM variants may be released into waterways, thereby posing a risk to humans. In this study, we collected effluent samples from a WWTP discharged into a canal in Tokyo Bay, Japan. Methods Testing included the complete genome sequencing of Escherichia coli GSH8M-2 isolated from the effluent as well as a gene network analysis. Results The complete genome sequencing of GSH8M-2 revealed that it was an NDM-5-producing E. coli strain sequence type ST542, which carries multiple antimicrobial resistance genes for β-lactams, quinolone, tetracycline, trimethoprim-sulfamethoxazole, florfenicol/chloramphenicol, kanamycin, and fosfomycin. The bla NDM-5 gene was found in the IncX3 replicon plasmid pGSH8M-2-4. Gene network analysis using 142 IncX3 plasmid sequences suggested that pGSH8M-2-4 is related to both clinical isolates of E. coli and Klebsiella species in Eastern Asia. GSH8M-2 also carries the bla CTX-M-55 gene in IncX1 plasmid pGSH8M-2-3. Conclusion This is the first report of environmental NDM-5-producing E. coli isolated from a WWTP in Japan. NDM-5 detection is markedly increasing in veterinary and clinical settings, suggesting that dual β-lactamases, such as NDM-5 and CTX-M-55, might be acquired through multiple steps in environment settings. Environmental contamination through WWTP effluents that contain producers of NDM variants could be an emerging potential health hazard. Thus, regular monitoring of WWTP effluents is important for the detection of antimicrobial-resistant bacteria that may be released into the waterways and nearby communities.

Characterization of urban wastewater treatment plant effluent from Tokyo using metagenomics and β-lactam-resistant Enterobacteriaceae isolates

“…The bla CTX−M variants were identi ed in wide variable plasmids, whereas carbapenemase genes (bla NDM , bla KPC , and bla IMP ) relatively showed a typical plasmid replicon with speci c distribution, suggesting that the regional-speci c distribution of carbapenemase [23] may be associated with its locality [24]. However, we have reported NDM-5-and CTX-M-55-coproducing E. coli GSH8M-2 isolated from WWTP e uent (WP8) in Tokyo Bay [25]. Such co-producers will be the next clonal dissemination with powerful activity against multiple β-lactams.…”

“…COD, chemical oxygen demand. a [50,70] b [25] See the information of whole-genome sequence for all isolates in Table S4.…”

Metagenomic survey and whole genome sequencing of antimicrobial resistant bacteria in the sewage of a Japanese hospital

“…In Sweden, carbapenemase-producing Klebsiella was also detected from clinical specimens, in Svartån River and the rivers downstream of it [11]. In Japan, KPC-2 producing Klebsiella [16,17] and NDM-5coproducing Escherichia coli [17] were detected from the e uent of urban wastewater treatment plants. Effective actions should be taken including advanced wastewater treatment processes such as ozone and UV treatment [47,106,107], and ultra ltration [108] to accelerate the removal of ARB in WWTP.…”

“…In addition to clinically isolated ARB, comparable ARB/ARGs have been detected from various environments around the world, including the e uent from wastewater treatment plants (WWTP) [4,5], lakes and rivers [6][7][8], and soil [9]. In particular, extended spectrum β-lactamase (ESBL)-producing E. coli or carbapenemase-producing organisms (CPOs) have been detected in rivers, lakes [10][11][12], and WWTP treated water [13][14][15] in several countries, posing a potential risk of infection, and Japan is no exception [16,17]. Moreover, hospital wastewater is the most ARB-contaminated source in WWTP [5,13,[18][19][20][21][22] and there is concern about the relationship between hospital wastewater and environmental pollution [23,24].…”

Identification of a recently dominate sublineage inSalmonella4,[5],12:i:- sequence type 34 isolated from food animals in Japan

“…During the past decade, blaCTX-M-55 has been increasingly found in Enterobacteriaceae isolated from humans, animals, and the environment (36). Recently, mcr genes were found in Salmonella Typhimurium/4, [5],12:i:-ST34 isolated from humans and swine in North America, Europe, Australia, and Asian countries other than Japan (8,11,34,37,38).…”