Co-Harboring of Beta-Lactamases and mcr-1 Genes in Escherichia coli and Klebsiella pneumoniae from Healthy Carriers and Backyard Animals in Rural Communities in Ecuador

Abstract

Few studies have addressed drug resistance of Enterobacterales in rural communities in developing countries. This study aimed to determine the coexistence of extended-spectrum β-lactamase (ESBL) and carbapenemase genes in Escherichia coli and Klebsiella pneumoniae strains carrying the mcr-1 gene in rural communities in Ecuador from healthy humans and their backyard animals. Sixty-two strains, thirty E. coli and thirty-two K. pneumoniae strains carrying the mcr-1 gene were selected from a previous study. PCR were performed for the presence of ESBLs and carbapenemase genes. The strains were further characterized, and the genetic relationship was studied with multi-locus sequencing typing (MLST) of seven housekeeping genes. Fifty-nine of the sixty-two mcr-1 isolates (95%) harbored at least on β-lactam resistance gene. The most prevalent ESBL genes were the blaTEM genes (present in in 80% of the E. coli strains) and the blaSHV gene (present in 84% of the K. pneumoniae strains). MSLT analysis revealed 28 different sequence types (ST); 15 for E. coli and 12 for K. pneumoniae, with most ST never described in humans and animals. The coexistence of mcr-1 and β-lactams resistant genes in E. coli and K. pneumoniae strains is alarming and threatens the efficacy of last-resort antibiotics. Our findings highlight backyard animals as a reservoir of mcr-1/β-lactams resistant genes.

Exploring Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli in Food-Producing Animals and Animal-Derived Foods

“…These investigations unveiled the existence of ESBL-producing E. coli strains, which possess considerable pathogenic potential. This discovery has sparked concerns regarding the concurrent presence of these strains in both animal and human populations, as well as the potential transmission of multidrug-resistant (MDR) strains from animals to humans [ 18 ]. In another study of ESBL-producing E. coli , plasmid analysis showed that the plasmid backbones across various lineages exhibit significant similarity and can be nearly identical among animals such as chickens, cattle, and swine, with similarities to plasmids isolated from humans [ 19 ].…”

Mobile Colistin Resistance (mcr) Gene-Containing Organisms in Poultry Sector in Low- and Middle-Income Countries: Epidemiology, Characteristics, and One Health Control Strategies

“…Since poultry vendors come into direct contact with birds, they are potentially a major source of the local transmission of MGCB originating from the poultry environment to human communities and vice versa. Chicken vendors in China [152], Peru [208], and Nepal [71] harboured mcr-1-positive E. coli. This suggests that these vendors possibly acquired the organism from the birds, probably due to poor hand hygiene after bird handling.…”

“…Among 274 E. coli isolated from 2018 to 2020, 44 (16.1%) isolates that coexpressed mcr-1 with 17 other resistance genes, including ESBL and PMQR genes, on various plasmids, such as IncI2, IncFI, and so on, were detected [208,209]. The isolates were extensively diversified, belonging to seven STs, including ExPEC ST746, ST10, and ST345, and they harboured virulence genes, including markers of APEC (ompT), EHEC (ast), EPEC (eae), and UPEC (papC) [209] (Table 1).…”