The First Report of mcr-1-Carrying Escherichia coli Originating from Animals in Serbia

Abstract

The aim of this study was continuous monitoring of the presence of mcr-1 to mcr-5 genes in Enterobacterales isolated from cattle, pigs, and domestic poultry at intensive breeding facilities in Northern Vojvodina, Serbia, from 1 January 1 to 1 October 2020. Out of 2167 examined samples, mcr-1 was observed in five E. coli isolates originating from healthy turkeys. Four isolates belonged to the phylogenetic group B1, and one isolate to the phylogenetic group A. Detected E. coli serogenotypes (somatic O and flagellar H antigens) were O8:H25 and O29:H25. Core-genome multi-locus sequence typing (cgMLST) revealed three ST58 isolates clustering together in Clonal Complex (CC) 155 and two singletons of ST641-CC86 and ST410-CC23, respectively. Clonotyping revealed CH4-32 (n = 3), CH6-53 (n = 1) and CH4-24 (n = 1). In all isolates, the mcr-1 gene was located on a large IncX4 replicon type plasmid. Eight virulence-associated genes (VAGs) typical of avian pathogenic E. coli (APEC) (fyuA, fimH, hlyF, iss, ompT, sitA, traT, iroN) were detected in four isolates. These isolates were investigated for susceptibility to four biocides and revealed MIC values of 0.125% for glutardialdehyde, of 0.00003–0.00006% for chlorohexidine, of 4–6% for isopropanol and of 0.001–0.002% for benzalkonium chloride. All obtained MIC values of the tested biocides were comparable to the reference strain, with no indication of possible resistance. This is the first report of mcr-1.1-carrying E. coli from Serbia. Although only samples from turkeys were mcr-positive in this study, continuous monitoring of livestock samples is advised to prevent a spill-over from animals to humans.

Development of Quality Control Ranges for Biocide Susceptibility Testing

“…The recently developed BST has already been used in some studies to test S. aureus from horses [19], primates [20], and beavers [21] as well as E. coli from animal origin [22,23]. It should be noted that conventional biocides, such as the ones described during this study, have a toxic potential.…”

Antimicrobial and Biocide Resistance among Canine and Feline Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii Isolates from Diagnostic Submissions

“…So far, very few MIC data on the tested biocide/bacteria combinations are available for comparison. A study on five mcr-1 -positive E. coli isolates from turkeys in Serbia identified MICs of 0.001 or 0.002% for benzalkonium chloride and 0.00003 or 0.00006% for chlorhexidine [ 57 ]. These benzalkonium MICs were also the two most frequently measured MICs in the present study.…”

Whole-Genome Sequencing-Based Resistome Analysis of Nosocomial Multidrug-Resistant Non-Fermenting Gram-Negative Pathogens from the Balkans

“…Until now, ten MCR-family genes and their variants have been described [ 193 , 194 ]. Despite that mcr genes have already been found on the Balkans [ 195 , 196 , 197 , 198 ], none of them were obtained from A. baumannii isolates. Recent studies from Croatia detected colistin resistant A. baumannii isolates, but the resistance mechanism was mediated by chromosomal mutations [ 199 , 200 ].…”