Emergence of optrA-Mediated Linezolid-Nonsusceptible Enterococcus faecalis in a Tertiary Care Hospital

다국어 초록 (Multilingual Abstract)

This study investigated resistance mechanisms and epidemiology of emerging linezolid-nonsusceptible Enterococcus faecalis (LNSEF) in a tertiary care hospital. LNSEF isolated from clinical samples were collected from November 2017 to June 2019. The isolates were investigated for linezolid resistance and the associated molecular mechanisms, including mutations of 23S rRNA domain V and acquisition of the cfr or optrA resistance gene. We used pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing for the molecular typing of the isolates. Among 4,318 E. faecalis isolates, 10 (0.23%) were linezolid-nonsusceptible. All LNSEF isolates were optrA-positive and cfr-negative. Of these isolates, five were sequence type (ST) 476, two ST585, one ST16, one ST16-like, and one ST480. Six LNSEF isolates obtained in the first year clustered to three types in the PFGE analysis: two ST476 isolates of type A, two ST585 isolates of type B, and two ST16 or ST16-like isolates of type C. Seven cases were of community-onset and three were hospital acquired, but total of eight were healthcare-associated including five community-onset. None of the patients had a history of linezolid treatment, and in one patient, we detected linezolid-susceptible E. faecalis one month before LNSEF detection. In conclusion, heterogenous clones of optrA-positive LNSEF emerged in the hospital mainly via community-onset.

참고문헌 (Reference)

1 Jung J, "The pitfall of cohort isolation in an outbreak of linezolid-resistant, vancomycin-resistant enterococci" 25 : 1568-1569, 2019

2 Huang J, "Retrospective analysis of genome sequences revealed the wide dissemination of optrA in Gram-positive bacteria" 72 : 614-616, 2017

3 Lee SM, "Resistance mechanisms of linezolid-nonsusceptible enterococci in Korea: low rate of 23S rRNA mutations in Enterococcus faecium" 66 : 1730-1735, 2017

4 Bender JK, "Rapid emergence of highly variable and transferable oxazolidinone and phenicol resistance gene optrA in German Enterococcus spp. clinical isolates" 52 : 819-827, 2018

5 Cui L, "Nationwide surveillance of novel oxazolidinone resistance gene optrA in Enterococcus isolates in China from 2004 to 2014" 60 : 7490-7493, 2016

6 Ruoyi Hua, "Molecular Epidemiology and Mechanisms of 43 Low-Level Linezolid-Resistant Enterococcus faecalis Strains in Chongqing, China" 대한진단검사의학회 39 (39): 36-42, 2019

7 Mendes RE, "Linezolid update: stable in vitro activity following more than a decade of clinical use and summary of associated resistance mechanisms" 17 : 1-12, 2014

8 Tenover FC, "Interpreting chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis: criteria for bacterial strain typing" 33 : 2233-2239, 1995

9 Pfaller MA, "Five-year summary of in vitro activity and resistance mechanisms of linezolid against clinically important Gram-positive cocci in the United States from the LEADER surveillance program (2011 to 2015)" 61 : e00609-e00617, 2017

10 Bae HG, "First report of a linezolid- and vancomycin-resistant Enterococcus faecium strain in Korea" 38 : 383-386, 2006

11 Cai J, "Faecal carriage of optrA-positive enterococci in asymptomatic healthy humans in Hangzhou, China" 25 : 630.e1-636.e6, 2019

12 Deshpande LM, "Evolving oxazolidinone resistance mechanisms in a worldwide collection of enterococcal clinical isolates: results from the SENTRY Antimicrobial Surveillance Program" 73 : 2314-2322, 2018

13 Sassi M, "Emergence of optrA-mediated linezolid resistance in enterococci from France, 2006-16" 74 : 1469-1472, 2019

14 Zhou W, "Distribution of the optrA gene in Enterococcus isolates at a tertiary care hospital in China" 17 : 180-186, 2019

15 Na SH, "Detection of oxazolidinone and phenicol resistant enterococcal isolates from duck feces and carcasses" 293 : 53-59, 2019

16 Argudín MA, "Detection of optrA-positive enterococci clinical isolates in Belgium" 38 : 985-987, 2019

17 Tamang MD, "Detection of novel oxazolidinone and phenicol resistance gene optrA in enterococcal isolates from food animals and animal carcasses" 201 : 252-256, 2017

18 Wang Y, "A novel gene, optrA, that confers transferable resistance to oxazolidinones and phenicols and its presence in Enterococcus faecalis and Enterococcus faecium of human and animal origin" 70 : 2182-2190, 2015

19 Zhang Y, "A high incidence and coexistence of multiresistance genes cfr and optrA among linezolid-resistant enterococci isolated from a teaching hospital in Wenzhou, China" 37 : 1441-1448, 2018