Young-Hee Jung1, Min-Hyeok Cha2, Gun-Jo Woo3, Young-Min Chi4. 1. Division of Biotechnology, College of Life Sciences, Korea University, Seoul, 02841, Republic of Korea. 2. Laboratory of Food Safety and Evaluation, Department of Biotechnology, Korea University Graduate School, Seoul, 02841, Republic of Korea. 3. Laboratory of Food Safety and Evaluation, Department of Biotechnology, Korea University Graduate School, Seoul, 02841, Republic of Korea. Electronic address: visionkorea@korea.ac.kr. 4. Division of Biotechnology, College of Life Sciences, Korea University, Seoul, 02841, Republic of Korea. Electronic address: ezeg@korea.ac.kr.
Abstract
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.
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.
Authors: Ilaria Baccani; Alberto Antonelli; Vincenzo Di Pilato; Marco Coppi; Tiziana Di Maggio; Michele Spinicci; Ana Liz Villagran; Carmen Revollo; Alessandro Bartoloni; Gian Maria Rossolini Journal: Antimicrob Agents Chemother Date: 2021-07-16 Impact factor: 5.191