白色假丝酵母菌对氟康唑敏感性及耐药机制研究

Study on the susceptibility to fluconazole and resistance mechanism of Candida albicans

目的研究本院临床分离的白色假丝酵母菌对氟康唑的耐药性及其ERG11基因突变情况。方法将临床标本接种至沙堡弱平板,用VITEK 2 Compact微生物分析系统鉴定所得菌株,保存所得白色假丝酵母菌;按照CLSI-M27-A3酵母菌微量肉汤稀释法进行氟康唑敏感性试验;选择部分代表菌株进行ERG11基因的PCR扩增、测序及比对分析。结果共分离得162株白色假丝酵母菌,其中来自痰液标本最多,占68.5%;氟康唑耐药株为11株,占6.8%;剂量依赖敏感株(S-DD)为16株,占9.9%;敏感株为135株,占83.3%;从7株氟康唑耐药和1株氟康唑敏感的白色假丝酵母菌ERG11基因中共发现22个点突变,其中错义突变3个,分别是V51E、D116E、E266D,其余均为同义突变;有2株氟康唑耐药菌株未发现错义突变。结论 ERG11基因的突变是白色假丝酵母菌对氟康唑耐药的重要机制,D116E可能是浙江地区白色假丝酵母菌对氟康唑耐药的主要突变位点;对于白色假丝酵母菌耐氟康唑机制的研究不应局限于ERG11基因的突变,应综合多方面因素。

Objective To study the resistance to fluconazole of Candida albicans and the mutation of ERG11 gene in our hospital.Methods The clinical specimens were inoculated to the sandcastle weak tablet,and Candida albicans was identificated by VITEK 2 Compact microbiological analysis system.Susceptibility test against fluconazole was done according to CLSI-m^27-A3 Saccharomycetes broth microdilution test.PCR amplification,sequencing and contrast analysis were done for ERG11 gene from representative isolates.Results 162 Candida albicans isolates were obtained,and most of them came from sputum specimens（ 68.5%）; 11 strains were fluconazole-resistant（ 6.8%）,16 strains were fluconazole-dose-dependent sensitive（ 9.9%）,135 strains were fluconazole-sensitive（ 83.3%）.22 mutation points were found from ERG11 gene of Candida albicans isolates in which 7 were fluconazole-resistant and 1 was fluconazole-sensitive.There were 3 missense mutations（ V51 E,D116E,E266D）,and the rest were silent mutations.2 fluconazole-resistant Candida albicans isolates were not found with any missense mutation.Conclusion ERG11 gene mutations are the important mechanism of Candida albicans＇ s resistance to fluconazole.D116 E might be the main mutation site of Candida albicans＇ resistance to fluconazole in Zhejiang.The research on the mechanism of Candida albicans＇ resistance to fluconazole should not only be limited to the ERG11 gene mutations,but also combine multiple factors.