Antibiotics (Jan 2025)
Antimicrobial Resistance Genes in Clinical <i>Escherichia coli</i> Strains from Livestock and Poultry in Shandong Province, China During 2015–2020
Abstract
Antimicrobial resistant (AMR) Escherichia coli (E. coli) isolated from animals may lead to antibiotic treatment failure and economic losses to farmers. The co-existence of antimicrobial resistant genes (ARGs) in the same isolate presents a major challenge for the prevention and control of infection in multidrug-resistant (MDR) Gram-negative organisms. There have been a lot of studies on the antibiotic resistance of E. coli in livestock and poultry, but few of them have focused on clinical pathogens. Objective: The aim of this study was to explore the genetic characteristics, co-occurrence, and correlations between ARGs of E. coli isolated from the pathological tissues of livestock and poultry in Shandong Province, East China during 2015–2020. Methods: A total of 158 E. coli strains were collected and subjected to antimicrobial susceptibility testing and sequencing by whole-genome Next Generation Sequencing (NGS). Results: MDR strains accounted for 46.20% of the 158 E. coli strains with the highest resistant rate of ciprofloxacin (71.52%). In addition, strains with blaNDM-5/mcr-1.1 and mcr-1.1/mcr-3.24 were found in chickens, while three strains with Tet(X4) were found in pigs. In addition, the most common serotypes detected were the O serotype (76/158) and H serotype (36/158). Moreover, seventy-one STs were found and the most common STs were ST10 (6.33%), ST155 (6.33%), and ST101 (5.69%). The genetic environment analysis of the phylogroups revealed that E. coli belonging to phylogroup B1, phylogroup A, and phylogroup C constituted 39.87%, 27.85%, and 15.19%, respectively. Through the correlation analysis, mcr genes were observed to have certain relationships with ARGS such as blaTEM, floR, catA/B, and oqx. Conclusions: This study demonstrates the high prevalence and gene diversity of MDR E. coli isolated from a clinic in Shandong Province, East China. We predicted the transmission risk of animal-borne Tet(X4)-bearing and mcr-harboring E. coli to public health and provided insight into the relationship of co-existence or co-transfer between mcr with ARGS. These relationships present a great challenge for the infection control of MDR Gram-negative organisms.
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