Plasmid-Mediated Colistin Resistance (mcr-1) in Escherichia coli from Non-Imported Fresh Vegetables for Human Consumption in Portugal.
Vera ManageiroDaniela Jones-DiasEugénia FerreiraManuela CaniçaPublished in: Microorganisms (2020)
In this study, we report the presence of the plasmid-mediated colistin resistance (PMCR)-encoding gene mcr-1 in an Escherichia coli isolate, INSali25, recovered from lettuce produced and marketed in Portugal. Colistin MIC from the vegetable E. coli isolate-determined by microdilution broth method according to EUCAST guidelines-revealed a non-wild-type phenotype of colistin (MIC 16 mg/L). To understand the genetic background of E. coli INSali25, we performed whole genome sequencing. Plasmid sequencing was also performed after plasmid DNA extraction from the transconjugant TcINSali25 (mcr-1). Directed bioinformatics analysis identified the mcr-1 gene in a 39,998 bp length contig, with an upstream region including the antibiotic resistance gene blaTEM-1 in a partial transposon Tn2, truncated by the insertion sequence IS26 and showing >99% identity with previously described mcr-1-harboring IncHI2 plasmids. Further in silico analysis showed the presence of additional genes conferring resistance to β-lactams (blaTEM-1), aminoglycosides (aadA1, aph(4)-Ia, aph(6)-Id, aac(3)-Iv), macrolides (mdf(A)-type), phenicol (floR-type), tetracycline (tetA), and sulphonamides (sul2). INSali25 isolate belonged to the ST1716 lineage and showed the fimH54 and fumC27 alleles. Lettuce is a vegetable that is commonly consumed fresh and not subjected to any cooking process, which may amplify human food safety risks. Moreover, the occurrence of plasmid-mediated colistin resistance in a sample that was not imported and was acquired in a large retail store reinforces the widespread distribution of mcr-1.
Keyphrases
- escherichia coli
- klebsiella pneumoniae
- genome wide
- endothelial cells
- copy number
- bioinformatics analysis
- genome wide identification
- biofilm formation
- wild type
- human health
- induced pluripotent stem cells
- risk assessment
- dna methylation
- pluripotent stem cells
- molecular docking
- acinetobacter baumannii
- gene expression
- cell free
- circulating tumor
- climate change