Overexpression of Both ERG11 and ABC2 Genes Might Be Responsible for Itraconazole Resistance in Clinical Isolates of Candida krusei.
Overexpression of Both ERG11 and ABC2 Genes Might Be Responsible for Itraconazole Resistance in Clinical Isolates of Candida krusei.
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ERG11 和 ABC2 基因的过度表达可能是克柔念珠菌临床分离株中伊曲康唑耐药的原因。
DOI：
10.1371/journal.pone.0136185
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Sui T
中科院分区：
文献类型：
--
作者：
He X;Zhao M;Chen J;Wu R;Zhang J;Cui R;Jiang Y;Chen J;Cao X;Xing Y;Zhang Y;Meng J;Deng Q;Sui T
目的探讨克柔念珠菌对伊曲康唑耐药的主要分子机制。采用聚合酶链反应（PCR）技术扩增16株克柔念珠菌临床分离株ERG 11基因编码的14个α-脱甲基酶基因，并测定其核苷酸序列，以检测点突变。同时，采用实时定量逆转录聚合酶链反应（qRT-PCR）方法检测克柔念珠菌ERG 11和外排转运蛋白（ABC 1和ABC 2）基因在伊曲康唑耐药（R）、伊曲康唑敏感剂量依赖（SDD）和伊曲康唑敏感（S）克柔念珠菌中mRNA水平的表达。所有克柔念珠菌临床分离株均存在ERG 11基因的7个点突变，其中6个为同义突变，1个为错义突变（C44 T）。但在三组中均发现错义突变。伊曲康唑耐药株ERG 11基因mRNA表达水平明显高于伊曲康唑敏感株和剂量敏感株（P分别为0.015和0.002）。伊曲康唑耐药组ABC 2基因mRNA表达水平显著高于其他两组，且随着伊曲康唑敏感性的降低，ABC 2基因mRNA表达水平逐渐升高（SDD组与S组比较P = 0.007，SDD + R组比较P = 0.016，S + R组比较P<0.001）。而ABC 1基因在伊曲康唑耐药株中表达较低。然而，ERG 11，ABC 1和ABC 2的mRNA水平在所有伊曲康唑耐药菌株中，在对伊曲康唑和伏立康唑均耐药的克柔念珠菌（CK 10）中表达最高。克氏梭菌临床分离株存在ERG 11基因多态性。ERG 11基因突变可能不参与克氏梭菌对伊曲康唑耐药的发展。ERG 11和ABC 2的过度表达可能是这些临床分离株获得性伊曲康唑耐药的原因。
To study the main molecular mechanisms responsible for itraconazole resistance in clinical isolates of Candida krusei. The 14α-demethylases encoded by ERG11 gene in the 16 C.krusei clinical isolates were amplified by polymerase chain reaction (PCR), and their nucleotide sequences were determined to detect point mutations. Meanwhile, ERG11 and efflux transporters (ABC1 and ABC2) genes were determined by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) for their expression in itraconazole-resistant (R), itraconazole-susceptible dose dependent (SDD) and itraconazole-susceptible (S) C.krusei at the mRNA level. We found 7-point mutations in ERG11 gene of all the C.krusei clinical isolates, including 6 synonymous mutations and 1 missense mutation (C44T). However, the missense mutation was found in the three groups. The mRNA levels of ERG11 gene in itraconazole-resistant isolates showed higher expression compared with itraconazole-susceptible dose dependent and itraconazole-susceptible ones (P = 0.015 and P = 0.002 respectively). ABC2 gene mRNA levels in itraconazole-resistant group was significantly higher than the other two groups, and the levels of their expression in the isolates appeared to increase with the decrease of susceptibility to itraconazole (P = 0.007 in SDD compared with S, P = 0.016 in SDD with R, and P<0.001 in S with R respectively). While ABC1 gene presented lower expression in itraconazole resistant strains. However, the mRNA levels of ERG11, ABC1 and ABC2 in a C.krusei (CK10) resistant to both itraconazole and voriconazole were expressed highest in all the itraconazole-resistant isolates. There are ERG11 gene polymorphisms in clinical isolates of C.krusei. ERG11 gene mutations may not be involved in the development of itraconazole resistance in C.krusei. ERG11 and ABC2 overexpression might be responsible for the acquired itraconazole resistance of these clinical isolates.