氟康唑耐药白色念珠菌upc2基因转录对mdr1转录的影响

Effect of upc2 gene transcription on mdr1 transcription in fluconazole-resistant Candida albicans

目的探讨氟康唑耐药白色念珠菌upc2基因转录对mdr1转录的影响。方法采用常规真菌分离鉴定法分离鉴定46株白色念珠菌,纸片扩散法测定其对5种唑类药物的敏感性,微量稀释法测定氟康唑的最低抑菌浓度(MIC),依据氟康唑MIC值将白色念珠菌分为三组(氟康唑敏感株、剂量依赖敏感株、耐药株)。应用实时荧光定量PCR检测各组白色念珠菌mdr1基因转录水平和ups2基因转录水平。采用Pearson相关分析mdr1基因转录水平和ups2基因转录水平之间的关系。结果耐药组白色念珠菌的upc2以及mdr1基因转录的相对倍数分别为(5.46±2.34)和(4.51±2.53),均高于敏感组白色念珠菌的(1.07±0.10)和(1.00±0.00),也高于剂量依赖敏感组白色念珠菌的(1.57±0.41)和(1.06±0.12),差异均有统计学意义(P<0.05);耐药组白色念珠菌的mdr1基因转录水平与upc2基因转录水平之间呈正相关(r=0.76,P<0.01)。结论白色念珠菌通过上调upc2基因转录水平而促进mdr1基因转录,进而导致白色念珠菌对氟康唑耐药。

Objective To investigate the effect of upc2 gene transcription on mdr1 transcription in fluconazoleresistant Candida albicans(C. albicans). Methods After 46 strains of C. albicans were isolated and identified from clinical samples by regular fungal isolation method, the drug susceptibility of the C. albicans strains to 5 kinds of azole was tested by Kirby-Bauer method, and the minimum inhibitory concentration(MIC) of C. albicans to fluconazole(FLU)was determined by microdilution method. According to the MIC level of C. albicans to FLU, the 46 strains were divided into three groups: FLU-sensitive strain(S group), dose-dependent FLU-sensitive strain(DS group), and FLU-resistant strain(R group). The mRNA transcription level of upc2 gene and mdr1 gene were measured by RT-PCR, and the Pearson correlation was used to analyze the relationship between the transcription level of mdr1 gene and upc2 gene. Results The relative ratio of upc2 and mdr1 gene transcription to quality-control strains of C. albicans were(5.46±2.34) and(4.51±2.53) for C. albicans in R group, which were significantly higher than(1.07±0.10) and(1.00±0.00) for C. albicans in S group and also higher than(1.57±0.41) and(1.06±0.12) in DS group(P<0.05). There was a positive relationship between the mdr1 gene transcription level and the upc2 gene transcription level(r=0.76, P<0.01). Conclusion The mdr1 gene transcription is promoted by up-regulation of upc2 gene transcription in C. albicans, which causes C. albicans resistance to FLU.