康替唑胺对利奈唑胺非敏感肠球菌的体外抗菌活性

In vitro antibacterial activity of contezolid against linezolid-insensitive Enterococcus

目的评价噁唑烷酮类新型抗菌药物康替唑胺对利奈唑胺非敏感肠球菌(LISE)的体外抗菌效能。方法收集解放军总医院第一医学中心2019-2022年临床分离的71株LISE,微量肉汤稀释法测定康替唑胺和利奈唑胺的最低抑菌浓度(MIC),并挑选利奈唑胺MIC分别为4、8和16 mg/L各2株,共计6株进行康替唑胺和利奈唑胺的最低杀菌浓度(MBC)、血清MIC以及杀菌曲线和抗菌药物后效应(PAE)比较,分析康替唑胺对LISE的体外抗菌活性的影响。结果康替唑胺对临床分离不同MIC的LISE显示出较好的抗菌活性,其中康替唑胺对屎肠球菌和粪肠球菌的MIC90为4 mg/L,低于利奈唑胺的MIC90(8 mg/L)。在含25%人血清蛋白的影响下,康替唑胺较利奈唑胺显示出更低的MIC(P<0.05)。在4倍MIC下,康替唑胺可在8~24 h对LISE具有良好的抑菌率。在相似的杀菌曲线下,康替唑胺较利奈唑胺拥有更低的MIC。在相似的PAE结果下,康替唑胺在对利奈唑胺耐药的肠球菌(LRE)拥有更低的MIC,显示康替唑胺抗菌活性更高。结论康替唑胺在体外实验对LISE抗菌活性高于利奈唑胺,临床治疗中可发挥重要作用。

OBJECTIVE To evaluate the in vitro antimicrobial activity of novel oxazolidinones contezolid against linezolid-insensitive Enterococcus(LISE).METHODS Totally 71 clinical isolates of LISE were collected from the First Medical Center of Chinese PLA General Hospital between 2019 and 2022.The minimum inhibitory concentrations(MICs)of contezolid and linezolid were determined by using broth microdilution method,6 isolates with MIC of linezolid 4,8 and 16 mg/L,2 isolates of each,were selected to compare the minimum bactericidal activity(MBC),serum MIC,killing curve and post-antibiotic effect(PAE)between contezolid and linezolid.The in vitro antibacterial activity of contezolid against the LISE was observed.RESULTS Contezolid demonstrated good antimicrobial activity against clinical isolates of LISE with varying MICs;the MIC_(90)of contezolid against Enterococcus faecalis and Enterococcus faecium was 4 mg/L,lower than 8 mg/L of linezolid.Contezolid showed lower MIC than linezolid under the impact of 25%serum protein(P<0.05).At a concentration of 4 times the MIC,contezolid exhibited favorable antibacterial rate against LISE within 8 to 24 hours.Contezolid showed the lower MIC than linezolid at the similar killing curve;contezolid showed the lower MIC against linezolid-resistant Enterococcus(LRE)than linezolid at the similar PAE,indicating that the antimicrobial activity of contezolid was remarkably higher.CONCLUSION The in vitro antimicrobial activity of contezolid against LISE is higher than that of linezolid,and contezolid plays an important role in clinical treatment.