Radezolid与Linezolid抑制粪肠球菌浮游菌和生物膜的效果评估

Evaluation of Radezolid and Linezolid's Inhibition of Enterococcus Faecalis Planktonic Bacteria and Biofilm

目的探讨新型噁唑烷酮类抗菌药物Radezolid和Linezolid对粪肠球菌浮游菌和生物膜形成的影响。方法收集临床分离的202株粪肠球菌,用琼脂稀释法测定Radezolid和Linezolid的最低抑菌浓度(MIC),PCR扩增23S rRNA结构域V区突变位点、核酸体蛋白基因rplC和rplD,cfr,cfr(B)以及optrA耐药基因的携带情况,结晶紫染色半定量方法检测药物抑制菌株成熟生物膜形成的能力。结果Radezolid(0.25、0.5 mg/L)对202株粪肠球菌的MIC50/MIC90比Linezolid(2、4 mg/L)低8倍;对于Linezolid非敏感的粪肠球菌,Radezolid体现更好的抑菌活性,Radezolid在1/4×MIC和1/8×MIC浓度下能更好地抑制粪肠球菌生物膜的形成。结论Radezolid比Linezolid更有效地对抗浮游菌,并在亚抑菌浓度下能更好地抑制粪肠球菌成熟生物膜的形成。

Objective To investigate the effects of new oxazolidinone antibacterial drugs Radezolid and Linezolid on enterococcus faecalis planktonic bacteria and biofilm formation.Methods 202 clinically isolated Enterococcus faecalis were collected,and the minimum inhibitory concentration(MIC)of Radezolid and Linezolid was determined by agar dilution method,PCR amplification of 23S rRNA domain V region mutation sites,nucleic acid protein genes rplC and rplD,cfr,cfr(B)and optrA drug resistance gene carrying status,semi-quantitative method of crystal violet staining to detect the formation of mature biofilms of drug-inhibited strains ability.Results The MIC50/MIC90 of Radezolid(0.25,0.5 mg/L)against 202 strains of Enterococcus faecalis is 8 times lower than that of Linezolid(2,4 mg/L);Radezolid shows better antibacterial activity against Linezolid non-sensitive Enterococcus faecalis,Radezolid can better inhibit the formation of Enterococcus faecalis biofilm at 1/4×MIC and 1/8×MIC concentrations.Conclusion Radezolid is more effective against planktonic bacteria than Linezolid,and it can better inhibit the formation of mature biofilm of Enterococcus faecalis at sub-inhibitory concentrations.