Characterization of mcr-1-Harboring Plasmids from Pan Drug-Resistant Escherichia coli Strains Isolated from Retail Raw Chicken in South Korea

Abstract

A number of studies from different countries have characterized mcr-1-harboring plasmids isolated from food; however, nothing has been reported about it in South Korea. In this study, we report the characterization of mcr-1 plasmids from pan drug-resistant (PDR) Escherichia coli strains isolated from retail food in the country. Colistin-resistant E. coli strains were isolated from retail raw chicken, and PCR was carried out to detect the mcr-1 gene. Whole genome sequencing of the mcr-1-positive strains was performed for further characterization. The results of whole genome sequencing revealed that all mcr-1 plasmids belonged to the IncI2 type. In addition to the mcr-1 plasmids, all of the isolates also carried additional plasmids possessing multiple antibiotic resistance genes, and the PDR was mediated by resistant plasmids except for fluoroquinolone resistance resulting from mutations in gyrA and parC. Interestingly, the mcr-1 plasmids were transferred by conjugation to other pathogenic strains including enterohemorrhagic E. coli (EHEC), enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC), Salmonella, and Klebsiella at the frequencies of 10−3−10−6, 10−2−10−5, 10−4−10−5, 10−4−10−6, and 10−5−10−6, respectively. The results showed that mcr-1 plasmids can be easily transmitted to pathogenic bacteria by conjugation.

Prevalence and Traits of Mobile Colistin Resistance Gene Harbouring Isolates from Different Ecosystems in Africa

“…The use of COL in humans was largely abandoned in the 1970s due to its neurotoxic and nephrotoxic effects alongside to the discovery and approval of new and effective antibiotics [ 2 ], but COL has been used in livestock for more than six decades in most countries in the world, including Africa [ 3 – 5 ]. In GNB, including Enterobacterales and nonfermenting GNB (such as Pseudomonas , Acinetobacter , and Aeromonas ), the major mechanism of COL resistance is by the addition of 4-amino-4-deoxy-L-arabinose (L-Ara4N) and phosphoethanolamine (pEtN) to the lipid A, a moiety of lipopolysaccharide (LPS), which decreases the electrostatic interaction between COL and LPS [ 6 , 7 ]. Before 2015, mutation in chromosomal genes, such as pmrAB , phoPQ , mgrB , and ccrB , were the known mechanisms of COL resistance.…”

A New Surface Charge Neutralizing Nano-Adjuvant to Potentiate Polymyxins in Killing Mcr-1 Mediated Drug-Resistant Escherichia coli

“…Thus, NDM-1 E. coli isolates used in this study are still susceptible to PolB in wild type cells. Meanwhile, NCCP isolates, containing the Mcr-1 expressing gene ( mcr-1 ) as a mobile element [ 35 ], showed 4-times more resistance to PolB (MIC = 3.2 μg·mL −1 ) compared to the BW25113 strain ( Table 1 ). As these isolates might have multiple resistant genes, it is difficult to see the sole Mcr-1 effect on susceptibility.…”

Prevalence and Genetic Characterization of mcr-1-Positive Escherichia coli Isolated from Retail Meats in South Korea

“…mcr-1-positive E. coli have also been found in humans and food animals in Korea [15][16][17]. However, few studies have reported mcr-1-bearing bacteria recovered from food samples in Korea [18].Since 2003, the Korean government has monitored and surveyed the antimicrobial resistance of bacteria collected from foods, such as retail meats, within the framework of the National Program on Antimicrobial Resistance Management [19]. mcr-1-positive E. coli were recently identified from retail meat samples.…”

“…mcr-1-positive E. coli have also been found in humans and food animals in Korea [15][16][17]. However, few studies have reported mcr-1-bearing bacteria recovered from food samples in Korea [18].…”