Occurrence of virulence genes in multidrug-resistant Escherichia coli isolates from Iberian wolves (Canis lupus signatus) in Portugal
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While much evidence supports the view that the total consumption of antimicrobials is the critical factor in selecting resistance, the possibility of resistant isolates and/or genes encoding resistance being transferred among different living communities has raised serious concerns. In the present study, Escherichia coli isolates recovered from faecal samples (n = 34) of Iberian wolves (Canis lupus signatus) were characterized for their antimicrobial drug susceptibility. Nearly two thirds of the isolates carried resistance to one or more antimicrobial drugs (in a panel of 19 antibiotics), and resistance to tetracycline, ampicillin and streptomycin was most widespread. By screening a set of 20 multidrug-resistant E. coli for virulence genes, we found strains positive for cdt, chuA, cvaC, eaeA, paa and bfpA, which was the most common virulence trait. Phylogenetic analyses have shown that the majority of these E. coli strains fall into phylogenetic groups A and B1. In this study, the diversity of extended-spectrum β-lactamase-producing strains was expressed by both polymorphism of the pulsed-field gel electrophoresis patterns and the presence of various resistance and virulence genes profiles. Finding the specific implications of these multi-resistant bacteria (hosting several virulence factors) in wolf conservation is a challenging topic to be addressed in further investigations.
KeywordsCanis lupus signatus E. coli Antimicrobial resistance Phylogenetic groups Virulence factors
Faecal samples from wolves were collected and genetically analysed during research projects funded by VentoMinho-Energias Renováveis, S.A. and ACHLI—Associação de conservação do habitat do lobo-ibérico. We thank M. Nakamura, D. Cadete, S. Pinto, A. Pedro and N. Santos for helping in sample collection and R. Godinho and D. Castro for the genetic identification of faecal samples. Wolves were captured under legal permits issued by ICNB/Ministry of Environment.
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