Molecular characteristics of extended-spectrum \u03b2-lactamase-producing Escherichia coli isolated from the rivers and lakes in Northwest China

Haixia Liu,Qinfan Li,Qian Peng,Jin Wang,Qian Zhao,Hongchao Zhou,Xiaoqiang Liu

doi:10.1186/s12866-018-1270-0

Haixia Liu, Qinfan Li + Show 5 more

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https://doi.org/10.1186/s12866-018-1270-0

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Abstract

BackgroundExtended-spectrum β-lactamases (ESBLs)-producing Escherichia coli (E. coli) isolates in environment water become progressively a potential threat to public health, while the detailed information about the ESBL-producing E. coli isolates in the rivers and lakes in Northwest China is scarce. In the present study, it was aimed to characterize the ESBL-producing E. coli isolated from the surface waters in Northwest China.ResultsA total of 2686 E. coli isolates were obtained from eleven rivers and lakes in Northwest China to screen for ESBL producers. Seventy-six (2.8%) isolates were classified as ESBL producers, and phylogenic groups D and A accounted for 59.2% of the ESBL producers. CTX-Ms were the predominant ESBLs genotype, and they were represented by seven blaCTX-M subtypes. blaCTX-M-14 was the most prevalent specific CTX-M gene, followed by blaCTX-M-9, blaCTX-M-123, blaCTX-M-15, blaCTX-M-27,blaCTX-M-1 and blaCTX-M-65. Moreover, 54 of the 76 ESBL producers carried at least one plasmid-mediated quinolone resistance (PMQR) gene, and aac(6′)-Ib-cr was predominant. The overall occurrence of virulence factors ranged from 1.3% (eae) to 48.7% (traT). Thirty-seven sequence types (STs) were confirmed among the 76 ESBL producers, and the predominant was ST10, which was represented by 10 isolates; importantly, clone B2-ST131, associated with severe infections in humans and animals, was detected three times.ConclusionThe prevalence of ESBL-producing E. coli from the rivers and lakes in Northwest China was low (2.8%), and the extraintestinal pathogenic E. coli (ExPEC) pathotype was the most commonly detected on the basis of the virulence factor profiles. 76.3% of ESBL producers harbored more than one β-lactamase gene, and blaCTX-M-14 was the predominant genotype. Notably, one ST131 isolate from Gaogan Canal simultaneously harbored blaCTX-M-9, blaCTX-M-15, blaCTX-M-123, blaKPC-2, blaNDM-1, blaOXA-2 as well as the PMQR genes qnrA, qnrS and aac(6′)-Ib-cr.

Highlights

Extended-spectrum β-lactamases (ESBLs)-producing Escherichia coli (E. coli) isolates in environment water become progressively a potential threat to public health, while the detailed information about the ESBLproducing E. coli isolates in the rivers and lakes in Northwest China is scarce
The prevalence of ESBL-producing E. coli from the rivers and lakes in Northwest China was low (2.8%), and the extraintestinal pathogenic E. coli (ExPEC) pathotype was the most commonly detected on the basis of the virulence factor profiles. 76.3% of ESBL producers harbored more than one β-lactamase gene, and blaCTX-M-14 was the predominant genotype
Antimicrobial susceptibility Among the 2686 E. coli isolates collected, 76 (2.8%) isolates were identified as the ESBL-producing isolates, which were unevenly distributed in 11 sampling sites at levels ranging from 1.1 to 6.4%

Summary

Introduction

Extended-spectrum β-lactamases (ESBLs)-producing Escherichia coli (E. coli) isolates in environment water become progressively a potential threat to public health, while the detailed information about the ESBLproducing E. coli isolates in the rivers and lakes in Northwest China is scarce. It was aimed to characterize the ESBL-producing E. coli isolated from the surface waters in Northwest China. E. coli isolates are characterized by their virulence properties and mechanisms of pathogenicity into the enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), shiga toxin-producing E. coli (STEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC) as well as extraintestinal pathogenic E. coli (ExPEC) [5, 6]. STEC isolates are defined as E. coli isolates expressing either stx or stx; EPEC isolates are defined as eae-harboring diarrheagenic E. coli isolates that do not possess the stx gene; ETEC isolates are characterized by estA and eltB; isolates carrying aggR and ipaH are referred to as EAEC and EIEC, respectively [7]. The pathotypes of the uncharacterized isolates can be inferred from their virulence properties

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