Dataset Information

Wastewater as a Probable Environmental Reservoir of Extended-Spectrum-β-Lactamase Genes: Detection of Chimeric β-Lactamases CTX-M-64 and CTX-M-123.

ABSTRACT: The presence of antimicrobial-resistant bacteria and resistance genes in aquatic environments is a serious public health concern. This study focused on Escherichia coli possessing bla_CTX-M genes in wastewater inflows. Twelve crude inflow water samples from wastewater treatment plant (WWTP) A and two samples each from three other WWTPs were collected in 2017 and 2018. A total of 73 E. coli isolates with 31 different sequence types (STs) harboring distinctive bla_CTX-M gene repertoires were detected. In WWTP A influents, bla_CTX-M-14 (14 isolates) was dominant, followed by bla_CTX-M-15 (12 isolates) and bla_CTX-M-27 (10 isolates). The chimeric bla_CTX-M-64 and bla_CTX-M-123 genes were each identified in one of the E. coli isolates from the same WWTP A inflow port. The bla_CTX-M-27 gene was associated with five of seven B2-ST131 isolates, including three isolates of the B2-O25b-ST131-H30R/non-Rx lineage. One of the remaining two isolates belonged to the B2-O25b-ST131-H30R/Rx lineage harboring the bla_CTX-M-15 gene. As for the B2-O25b-ST131-H30R/non-Rx lineage, two isolates with bla_CTX-M-27 were recovered from each of the WWTP B and D influents, and one isolate with bla_CTX-M-174 was also recovered from WWTP B influent. Whole-genome sequencing of chimeric bla_CTX-M-harboring E. coli isolates revealed that the bla_CTX-M-64 gene was integrated into the chromosome of ST10 E. coli B22 via ISEcp1-mediated transposition of a 9,467-bp sequence. The bla_CTX-M-123-carrying IncI1 plasmid pB64 was 109,169 bp in length with pST108. The overall findings suggest that wastewater may act as a probable reservoir of clinically significant clonal lineages mediating antimicrobial resistance genes and chimeric genes that have not yet been identified from human isolates of domestic origin in Japan.IMPORTANCE Global spread of CTX-M-type extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is a critical concern in both clinical and community settings. This dominance of CTX-M-type ESBL producers may be largely due to the successful international spread of epidemic clones, as represented by the extraintestinal pathogenic Escherichia coli (ExPEC) ST131. Our findings highlight the worrisome presence of diverse E. coli clones associated with humans, including ExPEC lineages harboring the most common bla_CTX-M variants in untreated wastewater samples. Moreover, the chimeric genes bla_CTX-M-64 and bla_CTX-M-123, which have not yet been identified from human isolates of domestic origin in Japan, were identified. Exposure to untreated wastewater through combined sewer overflow caused by heavy rains derived from abnormal weather change could pose a risk for human health due to ingesting those antimicrobial-resistant bacteria.

SUBMITTER: Tanaka H

PROVIDER: S-EPMC6821968 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Wastewater as a Probable Environmental Reservoir of Extended-Spectrum-β-Lactamase Genes: Detection of Chimeric β-Lactamases CTX-M-64 and CTX-M-123.

Tanaka Hayato H Hayashi Wataru W Iimura Masaki M Taniguchi Yui Y Soga Eiji E Matsuo Nao N Kawamura Kumiko K Arakawa Yoshichika Y Nagano Yukiko Y Nagano Noriyuki N

Applied and environmental microbiology 20191030 22

The presence of antimicrobial-resistant bacteria and resistance genes in aquatic environments is a serious public health concern. This study focused on Escherichia coli possessing blaCTX-M genes in wastewater inflows. Twelve crude inflow water samples from wastewater treatment plant (WWTP) A and two samples each from three other WWTPs were collected in 2017 and 2018. A total of 73 E. coli isolates with 31 different sequence types (STs) harboring distinctive bla ...[more]

PMID: 31519655

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Project description:CTX-M beta-lactamases were thought to be rare in the United States, but a recent study in Texas showed that up to 70% of extended-spectrum beta-lactamase (ESBL)-containing members of the Enterobacteriaceae family were CTX-M positive (J. S. Lewis, M. Herrera, B. Wickes, J. E. Patterson, and J. H. Jorgensen, Antimicrob. Agents Chemother. 51:4015-4021, 2007). We used PCR to detect CTX-M in all 291 extended-spectrum cephalosporin-resistant gram-negative bacteria isolated in our laboratory during 2007. Thirty (48%) Escherichia coli isolates, 6 (3%) Klebsiella sp. isolates, and 7 (100%) Proteus mirabilis isolates tested were CTX-M positive, with 15% of all Enterobacteriaceae tested being positive. The E. coli CTX-M groups were I (57%), IV (37%), II (3%), and not groupable (3%); three of the group IV isolates were positive for CTX-M-18, and three of the group I isolates were positive for CTX-M-15. One of seven positive P. mirabilis isolates was in group II, with the remainder being positive for a CTX-M-25-like beta-lactamase; and 33% of the Klebsiella sp. isolates were in group I or IV, with the remainder not being in groups I to IV. CTX-M-producing bacteria were isolated from urine (n = 13), blood (n = 13), wounds (n = 12), and the respiratory tract (n = 4). All 31 CTX-M-positive isolates tested for the presence of ESBL were confirmed to produce ESBLs by the use of tests recommended by the CLSI. Pulsed-field gel electrophoresis of the CTX-M-positive isolates showed that six P. mirabilis isolates were clonal and that there were seven different E. coli clusters. Five of seven P. mirabilis isolates were from blood cultures. The CLSI tests for the confirmation of ESBL production reliably detect these isolates if both cefotaxime and ceftazidime are tested, but only about half would be classified as a possible CTX-M producers on the basis of the antibiogram alone. A new panprimer set increases the ability to detect CTX-M-producing strains. CTX-M-positive bacteria are common in our geographic region, are often invasive, and, with the exception of P. mirabilis, are multiclonal.

Dataset Information

Wastewater as a Probable Environmental Reservoir of Extended-Spectrum-β-Lactamase Genes: Detection of Chimeric β-Lactamases CTX-M-64 and CTX-M-123.

Publications

Wastewater as a Probable Environmental Reservoir of Extended-Spectrum-β-Lactamase Genes: Detection of Chimeric β-Lactamases CTX-M-64 and CTX-M-123.

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