Transferable Resistance Gene optrA in Enterococcus faecalis from Swine in Brazil

Antimicrob Agents Chemother. 2020 May 21;64(6):e00142-20. doi: 10.1128/AAC.00142-20. Print 2020 May 21.

Abstract

OptrA is an ATP-binding cassette (ABC)-F protein that confers resistance to oxazolidinones and phenicols and can be either plasmid-encoded or chromosomally encoded. Here, we isolated 13 Enterococcus faecalis strains possessing a linezolid MIC of ≥4 mg/liter from nursery pigs in swine herds located across Brazil. Genome sequence comparison showed that these strains possess optrA in different genetic contexts occurring in 5 different E. faecalis sequence type backgrounds. The optrA gene invariably occurred in association with an araC regulator and a gene encoding a hypothetical protein. In some contexts, this genetic island was able to excise and form a covalently closed circle within the cell; this circle appeared to occur in high abundance and to be transmissible by coresident plasmids.

Keywords: Enterococcus faecalis; Tn554; optrA; oxazolidinones.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Brazil
  • Drug Resistance, Bacterial / genetics
  • Enterococcus faecalis* / genetics
  • Genes, Bacterial
  • Oxazolidinones*
  • Swine

Substances

  • Anti-Bacterial Agents
  • Oxazolidinones