Mechanisms of azole resistance in clinical isolates of Candida glabrata from two hospitals in China
Mechanisms of azole resistance in clinical isolates of Candida glabrata from two hospitals in China
复制标题
国内两家医院临床分离光滑念珠菌的唑类耐药机制
DOI：
10.2147/idr.s202058
复制
发表时间：
2019-01-01
影响因子：
3.9
通讯作者：
Hu, Xiaobo
中科院分区：
文献类型：
--
作者：
Yao, Dongting;Chen, Jia;Hu, Xiaobo
目的：光滑念珠菌已成为第二或第三最常见的非白念珠菌物种负责越来越多的全身感染。此外，其对唑类的高水平耐药性与高死亡率相关。本研究旨在了解医院内念珠菌感染及耐药特点。光滑念珠菌对唑类抗生素的耐药机制。光滑的患者和方法：59例临床C。从中国的两家医院收集光滑的分离物。通过ATB Fungus 3试纸条和CLSI M27肉汤微量稀释法测定菌株对抗真菌剂的敏感性。检测罗丹明6G的外排以评价外排泵的作用。通过实时PCR检测CgCDR 1、CgCDR 2、CgSNQ 2、CgERG 11和CgPDR 1的表达水平。通过基于PCR的DNA测序确定CgERG 11和CgPDR 1的序列。结果：59株C.光滑果对氟胞嘧啶和黄曲霉素B敏感。12株（20.3%）分离株被确定为氟康唑耐药，而13株（22.0%）和27株（45.7%）分离株分别被归类为伊曲康唑和伏立康唑的非野生型。唑类耐药菌株的外排泵作用强于唑类敏感菌株，且呈剂量依赖性，这与CgCDR 1和CgCDR 2显著上调（P<0. 05）相一致，而CgSNQ 2、CgERG 11和CgPDR 1差异不显著（P> 0. 05）。CgERG 11的测序结果表明CgERG 11没有改变，支持CgERG 11不参与C.光滑的在唑类耐药菌株中发现了4个CgPDR1错义突变，其中高频率的CgPDR1突变A848V以前未见报道。结论：外排泵功能是临床分离的念珠菌对氟康唑耐药的主要机制。glabrata的功能，需要进一步研究相关基因的破坏和全基因组表达来验证。
Purpose: Candida glabrata has emerged as the second or third most common non-albicans species responsible for an increasing number of systemic infections. Moreover, its high-level of resistance to azole is associated with a high mortality rate. This study aimed to evaluate nosocomial infections and resistance characteristics of C. glabrata and to explore the mechanism of azole resistance in C. glabrata. Patients and methods: Fifty-nine clinical C. glabrata isolates were collected from two hospitals in China. The susceptibility of the strains to antifungal agents was determined by both the ATB Fungus 3 strip and CLSI M27 broth microdilution method. Efflux of rhodamine 6G was examined to evaluate the effects of efflux pumps. The expression levels of CgCDR1, CgCDR2, CgSNQ2, CgERG11, and CgPDR1 were examined by real-time PCR. The sequences of CgERG11 and CgPDR1 were determined by PCR-based DNA sequencing. Results: All 59 isolates of C. glabrata were susceptible to flucytosine and amphotericin B. Twelve (20.3%) isolates were determined to be fluconazole-resistant, whereas 13 (22.0%) and 27 (45.7%) isolates were categorized as non-wild-type for itraconazole and voriconazole, respectively. Efflux pumps in azole-resistant isolates showed stronger effects than those in azole-susceptible-dose dependent isolates, which is consistent with the significant upregulation of CgCDR1 and CgCDR2 (P<0.05), whereas no obvious differences were found for CgSNQ2, CgERG11, and CgPDR1 (P>0.05). Sequencing of CgERG11 showed no alteration favoring the hypothesis that CgERG11 is not involved in the azole resistance of C. glabrata. Four CgPDR1 missense mutations were found in azole-resistant isolates, of which the high frequency of the CgPDR1 mutation, A848V, has not been reported previously. Conclusion: Efflux pump function is the main mechanism of resistance to fluconazole in our collected clinical isolates of C. glabrata, and further studies of the related gene disruption and genome-wide expression are needed to verify the function.