Laboratory Medicine ›› 2019, Vol. 34 ›› Issue (5): 428-432.DOI: 10.3969/j.issn.1673-8640.2019.05.009

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Activities of tedizolid in vitro against clinical Gram-positive cocci

LIN Wen, HUANG Kaifeng, YANG Han, HE Chunyan, CHEN Wenjing, SHU Wen, TANG Rong, YI Junwen, LIU Qingzhong()   

  1. Department of Clinical Laboratory,Shanghai General Hospital,Shanghai Jiaotong University,Shanghai 200080,China
  • Received:2018-06-28 Online:2019-05-30 Published:2019-05-28

Abstract:

Objective To investigate the drug susceptibilities of a novel oxazolidinone antibiotic,tedizolid,against clinical Gram-positive cocci,and to investigate the drug resistance mechanism in non-tedizolid susceptible isolates. Methods A total of 1 069 clinical Gram-positive cocci were collected. The isolates included 202 isolates of methicillin-resistant Staphylococcus aureus (MRSA),294 isolates of methicillin-susceptible Staphylococcus aureus (MSSA),115 isolates of coagulase-negative Staphylococcus,206 isolates of Enterococcus faecalis,55 isolates of Enterococcus faecium,159 isolates of Streptococcus agalactiae and 38 isolates of Streptococcus anginosus. The minimum inhibitory concentrations (MIC) of tedizolid and linezolid were determined by broth microdilution method and analyzed to clarify the difference of in vitro activities of them. Polymerase chain reaction (PCR) was performed to determine the drug resistance genes in tedizolid/linezolid non-susceptible isolates. Results All isolates of Staphylococcus (MIC≤0.5 μg/mL),Enterococcus faecium (MIC≤0.5 μg/mL) and Streptococcus (MIC≤0.25 μg/mL) were susceptible to tedizolid. The susceptibility rate of Enterococcus faecalis to tedizolid was 94.7%. Totally,11 tedizolid and linezolid non-susceptible isolates (tedizolid MIC=1 μg/mL,linezolid MIC=8 μg/mL) were found,which were positive for the novel oxazolidinone resistance gene, optrA. Tedizolid revealed 4-8-fold more effective than linezolid. Conclusions Tedizolid is a novel antibiotic for treating Gram-positive cocci infection,however,its drug resistance mediated by optrA in Enterococcus should be concerned.

Key words: Tedizolid, In vitro susceptibility, Gram-positive coccus, Oxazolidinone

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