摘要
目的研究利奈唑胺对肠球菌耐药的体外诱导作用并探讨其耐药机制。方法采用多步诱导法对9株临床分离肠球菌(5株粪肠球菌,4株屎肠球菌)以及质控菌株进行体外诱导耐药试验,采用琼脂平皿二倍稀释法测定诱导前、后的MIC,PCR法扩增耐药菌23s rRNA基因,DNA测序并进行序列分析比较。结果 10株肠球菌均诱导出稳定的利奈唑胺耐药株,MIC值与原菌株比较增加了8～64倍,所有诱导耐药菌株的23s rRNA基因中均出现点突变。测序结果与NCBI Blast中E.faecium ATCC27273比较,核苷酸序列第2576位发生G→U突变(G2576U)。结论利奈唑胺可诱导肠球菌产生获得性耐药,其耐药机制与肠球菌23s rRNA基因的点突变相关。
Objective To investigate the in vitro linezolid induced resistance in Enterococcus and its mechanism. Methods Multistep in vitro induction was conducted with 9 Enterococcus isolates （5 E＇. faecalls, 4 E. ,faecium） and 1 reference strain. MICs were determined by agar dilution method. Polymerase chain reaction （PCR） was used for 23srRNA gene analysis in resistant strains. DNA sequencing analysis was performed to compare with the sequence of E. faecium ATCC27273 in NCBI Blast. Results Resistance to linezolid was successfully induced in all the 10 strains with linezolid at concentrations from 8 × MIC to 64 × MIC. Point mutation was identified in 23srRNA gene in linezolid-resistant strains. When compared with NCBI Blast E. Jaeciurn ATCC27273, G-U mutation （G2576U） was found on locus 2576 of nueleotide sequence. Conclusions Linezolid can induce resistance in Enterococcus in vitro. This resistance may be associated with the point mutation of 23srRNA gene in Enterococcus.
出处
《中国感染与化疗杂志》
CAS
2011年第1期22-26,共5页
Chinese Journal of Infection and Chemotherapy
关键词
利奈唑胺
肠球菌
体外诱导
耐药菌株
最低抑菌浓度
点突变
linezolid
Enterococcus
induction in vitro
drug-resistant strain
minimum inhibitory concentration
point mutation
