AUTHOR=Ota Yusuke , Prah Isaac , Mahazu Samiratu , Gu Yoshiaki , Nukui Yoko , Koike Ryuji , Saito Ryoichi 

TITLE=Novel insights into genetic characteristics of blaGES-encoding plasmids from hospital sewage

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1209195

DOI=10.3389/fmicb.2023.1209195

ISSN=1664-302X

ABSTRACT=<sec id="sec1"><title>Introduction</title><p>The prevalence of Guiana extended-spectrum (GES)-type carbapenemase producers is increasing worldwide, and hospital water environments are considered as potential reservoirs. However, the genetic features underlying this resistance are not yet fully understood. This study aimed to characterize <italic>bla</italic><sub>GES</sub>-encoding plasmids from a single-hospital sewage sample in Japan.</p></sec><sec id="sec2"><title>Methods</title><p>Carbapenemase producers were screened using carbapenemase-selective agar and polymerase chain reaction. Whole-genome sequencing analyzes were performed on the carbapenemase-producing isolates.</p></sec><sec id="sec3"><title>Results</title><p>Eleven gram-negative bacteria (four <italic>Enterobacter</italic> spp., three <italic>Klebsiella</italic> spp., three <italic>Aeromonas</italic> spp., and one <italic>Serratia</italic> spp.) with <italic>bla</italic><sub>GES-24</sub> (<italic>n</italic> = 6), <italic>bla</italic><sub>GES-6</sub> (<italic>n</italic> = 4), and <italic>bla</italic><sub>GES-5</sub> (<italic>n</italic> = 1) were isolated from the sewage sample. Five <italic>bla</italic><sub>GES-24</sub> and a <italic>bla</italic><sub>GES-5</sub> were localized in IncP-6 plasmids, whereas three <italic>bla</italic><sub>GES-6</sub> plasmids were localized in IncC plasmids with IncF-like regions. The remaining <italic>bla</italic><sub>GES-6</sub> and <italic>bla</italic><sub>GES-24</sub> were, respectively, localized on IncFIB-containing plasmids with IncF-like regions and a plasmid with an IncW-like replication protein. The IncP-6 and IncW-like plasmids had a close genetic relationship with plasmids from Japan, whereas the IncC/IncF-like and IncFIB/IncF-like plasmids were closely related to those from the United States and Europe. All <italic>bla</italic><sub>GES</sub> genes were located on the class 1 integron cassette of the Tn<italic>3</italic> transposon-related region, and the IncC/IncF-like plasmid carried two copies of the integron cassette. Eight of the eleven <italic>bla</italic><sub>GES</sub>-encoding plasmids contained toxin-antitoxin system genes.</p></sec><sec id="sec4"><title>Discussion</title><p>The findings on the plasmids and the novel genetic content from a single wastewater sample extend our understanding regarding the diversity of resistance and the associated spread of <italic>bla</italic><sub>GES</sub>, suggesting their high adaptability to hospital effluents. These findings highlight the need for the continuous monitoring of environmental GES-type carbapenemase producers to control their dissemination.</p></sec>