Mechanisms of azole resistance in 52 clinical isolates of Candida tropicalis in China
Mechanisms of azole resistance in 52 clinical isolates of Candida tropicalis in China
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DOI：
10.1093/jac/dks481
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发表时间：
2013-04-01
影响因子：
5.2
通讯作者：
Peng, Yibing
中科院分区：
文献类型：
--
作者：
Jiang, Cen;Dong, Danfeng;Peng, Yibing
目的：从外排泵、呼吸系统状态和唑类抗真菌靶酶等方面探讨热带念珠菌对唑类药物的耐药机制。从中国4个省的5家医院采集热带假单胞菌，进行抗真菌药敏试验。分别用罗丹明6 G和罗丹明123检测外排泵和呼吸状态。通过实时定量RT-PCR定量转运蛋白相关基因CDR 1和MDR 1、线粒体基因CYTb以及ERG 11。同时，麦角甾醇的含量进行了分析，使用液相色谱-质谱/质谱。构建了ERG 11缺陷型（erg 11 Delta）酿酒酵母菌株，以研究ERG 11突变的功能。结果：MIC显示31株分离株对至少一种抗真菌唑类药物具有耐药性。使用罗丹明123的流式细胞仪显示呼吸增加的唑类耐药菌株，但CYTb没有过表达。罗丹明6 G的外排没有发现显著差异，这与CDR 1和MDR 1的表达水平相当一致。与此相反，唑类耐药菌株过表达ERG 11，并表现出麦角甾醇含量增加。此外，对三种唑类抗真菌药耐药的菌株比仅对氟康唑或伊曲康唑耐药的菌株表达更高水平的ERG 11 mRNA。在唑类耐药菌株中发现了两个ERG 11突变，Y132 F和S154 F，并可通过在S.结论：ERG 11基因的上调和突变介导了C.热带植物
Objectives: To explore the mechanisms underlying azole resistance in clinical isolates of Candida tropicalis collected in China by focusing on their efflux pumps, respiratory status and azole antifungal target enzyme.Methods: Fifty-two clinical isolates of C. tropicalis were collected from five hospitals in four provinces of China and antifungal susceptibility tests were performed. Rhodamine 6G and rhodamine 123 were used to investigate the efflux pumps and respiratory status, respectively. Transporter-related genes CDR1 and MDR1, mitochondrial gene CYTb, as well as ERG11, were quantified by real-time RT-PCR. Meanwhile, ergosterol content was analysed using liquid chromatography-mass spectrometry/mass spectrometry. An ERG11-deficient (erg11 Delta) Saccharomyces cerevisiae strain was generated to study the function of mutations in ERG11.Results: MICs showed that 31 isolates were resistant to at least one type of azole antifungal. Flow cytometry using rhodamine 123 revealed increased respiration for the azole-resistant isolates, but CYTb was not overexpressed. No significant difference in the efflux of rhodamine 6G was found, which was consistent with the comparable expression levels of CDR1 and MDR1. In contrast, the azole-resistant isolates overexpressed ERG11 and showed increased ergosterol content. Moreover, the isolates resistant to three azole antifungals expressed higher levels of ERG11 mRNA than those resistant to only fluconazole or itraconazole. Two ERG11 mutations, Y132F and S154F, were found in azole-resistant isolates and could be shown to mediate azole resistance by expression in S. cerevisiae.Conclusions: The up-regulation and mutations of ERG11 mediate azole resistance of C. tropicalis.