Wanqing Zhou1, Shuo Gao1, Hongjing Xu2, Zhifeng Zhang1, Fei Chen1, Han Shen3, Chunni Zhang4. 1. Department of Laboratory Medicine, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, 321# Zhongshan Road, Gulou District, Nanjing, Jiangsu Province 210008, PR China. 2. Department of Laboratory Medicine, Jiangning District Hospital of Traditional Chinese Medicine, 657# Tianyin Avenue, Jiangning District, Nanjing, Jiangsu Province 211100, PR China. 3. Department of Laboratory Medicine, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, 321# Zhongshan Road, Gulou District, Nanjing, Jiangsu Province 210008, PR China. Electronic address: shenhan10366@sina.com. 4. Department of Clinical Laboratory, Jinling Hospital, Nanjing University School of Medicine, Nanjing University, 305# East Zhongshan Road, Qinhuai District, Nanjing, Jiangsu Province 210008, PR China. Electronic address: zchunni27@hotmail.com.
Abstract
OBJECTIVES: Linezolid-resistant Enterococcus have spread worldwide. This study investigated the prevalence of linezolid-non-susceptible Enterococcus (LNSE) and the potential mechanism and molecular epidemiology of LNSE isolates from Nanjing, China. METHODS: Linezolid susceptibility of 2555 Enterococcus was retrospectively determined by Etest. Vancomycin and teicoplanin MICs were determined for LNSE by Etest. PCR and DNA sequencing were used to investigate the potential molecular mechanism. Clonal relatedness between LNSE isolates was analysed by MLST. WGS was also performed. RESULTS: A total of 27 Enterococcus isolates (24 Enterococcus faecalis, 3 Enterococcus faecium) with linezolid MICs of 4-48μg/mL were identified, among which 20 E. faecalis and 3 E. faecium were positive for optrA. No mutations were found in genes encoding domain V of 23S rRNA or ribosomal proteins L3/L4; the cfr gene was not found. The 24 linezolid-non-susceptible E. faecalis were classified into eight STs (ST16, ST480, ST476, ST631, ST585, ST428, ST25 and ST689). The three linezolid-non-susceptible E. faecium were classified as ST17, ST400 and ST195. Comparison of the deduced OptrA amino acid sequences of the 23 optrA-positive isolates by PCR-based sequencing and WGS with that of the original OptrA from E. faecalis E349 revealed seven variants (KD, EDP, EDM, D, EDD, RDK and DP) in 16 isolates, with no mutations in the remaining 7 isolates. optrA was found downstream of fexA by searching the pE349 sequence based on WGS data. CONCLUSIONS: Emergence of LNSE with optrA-mediated resistance and clonal dissemination of ST16 E. faecalis in our hospital may pose a potential public-health threat.
OBJECTIVES:Linezolid-resistant Enterococcus have spread worldwide. This study investigated the prevalence of linezolid-non-susceptible Enterococcus (LNSE) and the potential mechanism and molecular epidemiology of LNSE isolates from Nanjing, China. METHODS:Linezolid susceptibility of 2555 Enterococcus was retrospectively determined by Etest. Vancomycin and teicoplanin MICs were determined for LNSE by Etest. PCR and DNA sequencing were used to investigate the potential molecular mechanism. Clonal relatedness between LNSE isolates was analysed by MLST. WGS was also performed. RESULTS: A total of 27 Enterococcus isolates (24 Enterococcus faecalis, 3 Enterococcus faecium) with linezolid MICs of 4-48μg/mL were identified, among which 20 E. faecalis and 3 E. faecium were positive for optrA. No mutations were found in genes encoding domain V of 23S rRNA or ribosomal proteins L3/L4; the cfr gene was not found. The 24 linezolid-non-susceptible E. faecalis were classified into eight STs (ST16, ST480, ST476, ST631, ST585, ST428, ST25 and ST689). The three linezolid-non-susceptible E. faecium were classified as ST17, ST400 and ST195. Comparison of the deduced OptrA amino acid sequences of the 23 optrA-positive isolates by PCR-based sequencing and WGS with that of the original OptrA from E. faecalis E349 revealed seven variants (KD, EDP, EDM, D, EDD, RDK and DP) in 16 isolates, with no mutations in the remaining 7 isolates. optrA was found downstream of fexA by searching the pE349 sequence based on WGS data. CONCLUSIONS: Emergence of LNSE with optrA-mediated resistance and clonal dissemination of ST16 E. faecalis in our hospital may pose a potential public-health threat.
Authors: Lara M Almeida; François Lebreton; Anthony Gaca; Paulo M Bispo; Jose T Saavedra; Rodrigo N Calumby; Luciano M Grillo; Ticiano G Nascimento; Pedro H Filsner; Andrea M Moreno; Michael S Gilmore Journal: Antimicrob Agents Chemother Date: 2020-05-21 Impact factor: 5.191
Authors: Stefan Schwarz; Wanjiang Zhang; Xiang-Dang Du; Henrike Krüger; Andrea T Feßler; Shizhen Ma; Yao Zhu; Congming Wu; Jianzhong Shen; Yang Wang Journal: Clin Microbiol Rev Date: 2021-06-02 Impact factor: 50.129