Feng Wenli, Yang Jing, Xi Zhiqin, Qiao Zusha, Lv Yaping, Wang Yiru, Ma Yan, Wang Yanqing, Cen Wen
Department of Dermatovenereology, The Second Hospital of Shanxi Medical University , Taiyuan City, Shanxi Province, China .
Microb Drug Resist. 2017 Jul;23(5):563-570. doi: 10.1089/mdr.2016.0095. Epub 2016 Dec 15.
We aimed to investigate whether mutations and/or overexpressions of ERG4 and ERG11 genes were involved in drug resistance to azoles in Candida albicans.
Totally, 34 clinical isolates of C. albicans were included in this study. Antimicrobial susceptibility tests, including 5-fluorocytosine (5-FC), amphotericin B (AMB), fluconazole (FCA), itraconazole (ITR), and voriconazole (VRC), were performed by broth microdilution method. Mutations in the ERG4 and ERG11 genes sequence were detected. The messenger RNA (mRNA) levels of ERG4 and ERG11 were measured by quantitative real-time polymerase chain reaction. The correlation of the expression levels of ERG4 with ERG11 genes in susceptible isolates and resistant isolates was analyzed by Pearson's correlation analysis.
Among 34 C. albicans isolates, 52.94%, 70.59%, and 50.00% isolates were resistant to FCA, ITR, and VRC, respectively. Sequencing results revealed that only 2 silent mutations were found in ERG4 gene, while 10 amino acid substitutions, including 6 reported previously and 4 new identified, were frequently found in ERG11 gene. The mRNA levels of ERG4 and ERG11 genes were significantly elevated in resistant compared with susceptible C. albicans isolates. Furthermore, the mRNA level of ERG4 was positively correlated with ERG11 in susceptible but not resistant C. albicans isolates.
The resistance to azoles may be associated with the mutations in ERG11 but not ERG4 gene in C. albicans isolates. In addition, overexpressed ERG4 and ERG11 genes are found in resistant C. albicans isolates, and the mRNA levels of ERG4 may be irrelevant to ERG11 in resistant C. albicans isolates.
我们旨在研究ERG4和ERG11基因的突变和/或过表达是否与白色念珠菌对唑类药物的耐药性有关。
本研究共纳入34株白色念珠菌临床分离株。采用肉汤微量稀释法进行抗菌药物敏感性试验，包括5-氟胞嘧啶（5-FC）、两性霉素B（AMB）、氟康唑（FCA）、伊曲康唑（ITR）和伏立康唑（VRC）。检测ERG4和ERG11基因序列的突变。通过定量实时聚合酶链反应测量ERG4和ERG11的信使核糖核酸（mRNA）水平。采用Pearson相关分析分析敏感株和耐药株中ERG4与ERG11基因表达水平的相关性。
在34株白色念珠菌分离株中，分别有52.94%、70.59%和50.00%的分离株对FCA、ITR和VRC耐药。测序结果显示，ERG4基因仅发现2个沉默突变，而ERG11基因经常发现10个氨基酸替换，其中包括6个先前报道的和4个新鉴定的。与敏感的白色念珠菌分离株相比，耐药株中ERG4和ERG11基因的mRNA水平显著升高。此外，在敏感的白色念珠菌分离株中ERG4的mRNA水平与ERG11呈正相关，但在耐药株中并非如此。
白色念珠菌分离株对唑类药物的耐药性可能与ERG11基因的突变有关，而与ERG4基因无关。此外，在耐药的白色念珠菌分离株中发现ERG4和ERG11基因过表达，并且在耐药的白色念珠菌分离株中ERG4的mRNA水平可能与ERG11无关。
