Microorganisms (Sep 2022)

Occurrence and Characterisation of Colistin-Resistant <i>Escherichia coli</i> in Raw Meat in Southern Italy in 2018–2020

  • Gaia Nobili,
  • Gianfranco La Bella,
  • Maria Grazia Basanisi,
  • Annita Maria Damato,
  • Rosa Coppola,
  • Rachele Migliorelli,
  • Valeria Rondinone,
  • Pimlapas Leekitcharoenphon,
  • Valeria Bortolaia,
  • Giovanna La Salandra

DOI
https://doi.org/10.3390/microorganisms10091805
Journal volume & issue
Vol. 10, no. 9
p. 1805

Abstract

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Colistin is a last-resort drug for the treatment of infections by carbapenem-resistant Enterobacteriaceae, and the emergence of colistin resistance poses a serious clinical challenge. The aim of this study was to investigate the occurrence of colistin-resistant Escherichia coli in retail meat in Southern Italy in 2018–2020. Of 570 samples, 147 contained E. coli. Two out of 147 (1.4%) E. coli showed a non-wild-type phenotype to colistin and harboured mcr-1. mcr-1 was also detected in a wild-type isolate, resulting in a 2% mcr prevalence. mcr-1-positive isolates originated from turkey meat collected in Apulia (n = 2) and Basilicata (n = 1). A whole-genome sequencing analysis confirmed mcr-1.2 and mcr-1.1 in two and one isolate, respectively. The strains were diverse, belonging to three multi-locus sequence types (ST354, ST410, SLV of ST10) and harbouring genes mediating resistance to antimicrobials in two, six and seven classes. mcr-1 was carried by IncX4 plasmids with high nucleotide similarity to IncX4 plasmids harbouring mcr-1.2 and mcr-1.1 in Enterobacterales from different sources and geographical regions. This is the first study reporting updates on E. coli non-wild-type to colistin from retail meat in Southern Italy, highlighting the importance of phenotypic and genotypic antimicrobial resistance surveillance to contain the dissemination of mcr among E. coli.

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