Characteristics of the plasmid-mediated colistin-resistance gene mcr-1 in Escherichia coli isolated from a veterinary hospital in Shanghai

Abstract

The mobile colistin-resistance (mcr)-1 gene is primarily detected in Enterobacteriaceae species, such as Escherichia coli and Salmonella enterica, and represents a significant public health threat. Herein, we investigated the prevalence and characteristics of mcr-1-positive E. coli (MCRPEC) in hospitalized companion animals in a pet hospital in Shanghai, China, from May 2021 to July 2021. Seventy-nine non-duplicate samples were collected from the feces (n = 52) and wounds (n = 20) of cats and dogs and the surrounding hospital environment (n = 7). Seven MCRPEC strains, identified using screening assays and polymerase chain reaction, exhibited multidrug-resistant phenotypes in broth-microdilution and agar-dilution assays. Based in whole-genome sequencing and bioinformatics analyses, all seven isolates were determined to belong to sequence type (ST) 117. Moreover, the Incl2 plasmid was prevalent in these MCRPEC isolates, and the genetic environment of the seven E. coli strains was highly similar to that of E. coli SZ02 isolated from human blood. The isolates also harbored the β-lactamase gene blaCTX-M-65, and florfenicol resistance gene floR, among other resistance genes. Given that horizontal transfer occurred in all seven strains, E. coli plasmid transferability may accelerate the emergence of multidrug-resistant bacteria and may be transmitted from companion animals to humans. Therefore, the surveillance of MCRPEC isolates among companion animals should be strengthened.

Fosfomycin Resistance in Bacteria Isolated from Companion Animals (Dogs and Cats)

“…Seven E. coli isolates positive for the colistin-resistance gene mcr-1 were detected. All of them carried the fosA3 gene and also exhibited an MDR phenotype [ 76 ]. The spread of the mcr-1 gene in companion animals was associated with plasmid transmission, horizontal and vertical.…”

“…FosA and fosA3 are the dominant relevant ARGs in Gram-negative bacteria, located in chromosomal DNA and plasmids, respectively. The location of fosA3 gene in mobile genetic elements creates concerns about the wide dissemination of the resistance through the transmission of these elements among different bacterial strains [ 50 , 51 , 52 , 56 , 58 , 69 , 70 , 76 ]. Acquired fosA3 -mediated resistance is the dominant mechanism detected in E. coli isolates, while it is only occasionally detected [ 56 , 58 ] in other bacterial species of the Enterobacteriaceae family.…”

“…Acquired fosA3 -mediated resistance is the dominant mechanism detected in E. coli isolates, while it is only occasionally detected [ 56 , 58 ] in other bacterial species of the Enterobacteriaceae family. Furthermore, fosA3 and bla CTX-M are regularly co-carried [ 50 , 51 , 52 , 56 , 70 , 76 ] and possibly co-transferred through common mobile genetic elements. FosB is the main ARG identified in Gram-positive cocci [ 49 , 53 , 74 , 79 ].…”

“…Aminoglycosides and tetracyclines are the most frequently observed classes. This co-selection issue is highlighted in a number of the included studies [ 50 , 51 , 52 , 76 ]. Moreover, recent studies have identified the colonization of pets by MDR bacteria after antibiotic treatment with commonly used drugs, such as β-Lactams and Fluoroquinolones, and thus the requirement for increased surveillance efforts [ 87 , 88 ].…”

Detection of antibiotic-resistant canine origin Escherichia coli and the synergistic effect of magnolol in reducing the resistance of multidrug-resistant Escherichia coli

“…To extract genomic DNA, washed bacteria were boiled in sterile ultrapure water for 10 min. After centrifugation at 14,000 rpm for 15 min, the resulting supernatant was used as the DNA template for polymerase chain reaction (PCR) assays ( 4 , 20 ) using primers specific for 16S rDNA to identify the isolates, as described previously ( 21 , 22 ). PCR assays were performed in a final volume of 20 μL, consisting of 10 μL of master mix (Dining, China), 1 μL of each forward and reverse primer, 1 μL of DNA template, and 7 μL of nuclease-free water.…”