Characterization of oxazolidinone and phenicol resistance genes in non-clinical enterococcal isolates from Korea

Young Hee Jung, Min Hyeok Cha, Gun Jo Woo, Young Min Chi

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Objectives: To investigate the distribution and genetic characteristics of linezolid-resistant enterococci. Methods: Enterococcus faecalis and Enterococcus faecium strains were isolated from pigs, equipment, grounds, and employees of 19 Korean swine farms in 2017. Antimicrobial susceptibility testing was then performed and linezolid resistance genes were detected via PCR. For genetic epidemiological characterization, multilocus sequence typing and whole-genome sequencing data were analysed. Results: Twenty-eightE. faecalis and five E. faecium strains were isolated from 1026 samples obtained from the 19 farms. Ten sequence types were identified among the E. faecalis strains, of which ST256 (42.9%) and ST86 (25%) were the most abundant. The oxazolidinone and phenicol resistance genes poxtA, optrA, and fexA were detected in isolates of E. faecalis (100%, 85.7%, and 67.9%, respectively) and E. faecium (100%, 60%, and 80%, respectively). The minimum inhibitory concentrations of linezolid in these isolates ranged from 2 mg/L to 12 mg/L. The whole-genome sequencing data indicated that fexA was located upstream of poxtA. Conclusions: This is the first study to report the detection of poxtA in isolates that were both susceptible and resistant to linezolid in Korea. These results demonstrate the importance of antimicrobial resistance monitoring programmes, including regular antimicrobial susceptibility testing and resistance gene expression analysis, to facilitate the control of the spread of antibiotic resistance in non-clinical settings in Korea.

Original languageEnglish
Pages (from-to)363-369
Number of pages7
JournalJournal of Global Antimicrobial Resistance
Publication statusPublished - 2021 Mar

Bibliographical note

Funding Information:
This study was supported by the Korea National Institute of Health (grant number 2017ER540601 ) and Korea University Grant .

Publisher Copyright:
© 2021 The Author(s)


  • Drug resistance gene
  • Multilocus sequence typing
  • Oxazolidinone
  • Phenicol
  • Whole-genome sequencing

ASJC Scopus subject areas

  • Microbiology
  • Immunology and Allergy
  • Immunology
  • Microbiology (medical)


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