Whole-Genome Sequencing-Based Characteristics in Extended-Spectrum Beta-Lactamase-Producing Escherichia coli Isolated from Retail Meats in Korea.

Hyosun Kwak,Hansol Kim,Migyeong Kim,Yonghoon Kim,Sangryeol Ryu,Seokhwan Kim

doi:10.3390/microorganisms8040508

Abstract

The spread of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) has posed a critical health risk to both humans and animals, because resistance to beta-lactam antibiotics makes treatment for commonly infectious diseases more complicated. In this study, we report the prevalence and genetic characteristics of ESBL-ECs isolated from retail meat samples in Korea. A total of 1205 E. coli strains were isolated from 3234 raw meat samples, purchased from nationwide retail stores between 2015 and 2018. Antimicrobial susceptibility testing was performed for all isolates by a broth microdilution method, and the ESBL phenotype was determined according to the Clinical and Laboratory Standards Institute (CLSI) confirmatory method. All ESBL-EC isolates (n = 29) were subjected to whole-genome sequencing (WGS). The antimicrobial resistance genes, plasmid incompatibility types, E. coli phylogroups, and phylogenetic relations were investigated based on the WGS data. The prevalence of ESBL-ECs in chicken was significantly higher than that in other meat samples. The results in this study demonstrate that clonally diverse ESBL-ECs with a multidrug resistance phenotype were distributed nationwide, although their prevalence from retail meat was 0.9%. The dissemination of ESBL-ECs from retail meat poses a potential risk to consumers and food-handlers, suggesting that the continuous surveillance of ESBL-ECs in retail meat should be conducted at the national level.

Highlights

Escherichia coli is a ubiquitous bacterium residing in the intestinal tract of humans and animals, environment, and food
E. coli can serve as an important reservoir of antimicrobial resistance (AMR) genes, that may be transferred to human pathogenic bacteria [4,5,6]
Out of 1205 E. coli strains isolated from meat samples, 120 strains were resistant to third-generation cephalosporins and were tested for the extended-spectrum beta-lactamase (ESBL) phenotype

Summary

Introduction

Escherichia coli is a ubiquitous bacterium residing in the intestinal tract of humans and animals, environment, and food. E. coli can serve as an important reservoir of antimicrobial resistance (AMR) genes, that may be transferred to human pathogenic bacteria [4,5,6]. The spread of antimicrobial-resistant E. coli, especially extended-spectrum beta-lactamase (ESBL)-producing E. coli (ESBL-ECs), has become a threat to human as well as animal health worldwide [7]. The resistance to beta-lactams, one of the most widely used antibiotics, makes treatment for common infectious diseases caused by ESBL-ECs more complicated, as it involves hospitalization and intravenous carbapenem administration, instead of taking oral antibiotics at home [9,10,11]. As some ESBL genes are located on mobile elements such as plasmids and may be transferred to various bacterial species [12,13], the prevalence of ESBL-producing isolates from humans, livestock, and even food is rapidly increasing worldwide [14,15]. The selection pressure due to the ongoing overuse and misuse of antimicrobial agents possibly accelerates the emergence of antimicrobial-resistant bacteria [20,21]

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Results