从临床标本中分离出的近平滑念珠菌复合体的毒力因子、抗真菌药敏性和唑类耐药的分子机制。
Virulence factors, antifungal susceptibility and molecular mechanisms of azole resistance among Candida parapsilosis complex isolates recovered from clinical specimens.
机构信息
Laboratory of Parasitology - Mycology, UH Habib Bourguiba, Sfax, Tunisia.
Laboratory of Fungal and Parasitic Molecular Biology, School of Medicine, University of Sfax, Sfax, Tunisia.
出版信息
J Biomed Sci. 2017 Sep 4;24(1):67. doi: 10.1186/s12929-017-0376-2.
BACKGROUND
The aim of this study was to determine the biofilm formation, the extracellular enzymatic activities of 182 clinical isolates of the Candida parapsilosis complex.
METHODS
Molecular identification of the C. parapsilosis species complex was performed using PCR RFLP of SADH gene and PCR sequencing of ITS region. The susceptibility of ours isolates to antifungal agents and molecular mechanisms underlying azole resistance were evaluated.
RESULTS
63.5% of C. parapsilosis were phospholipase positive with moderate activity for the majority of strains. None of the C. metapsilosis or C. orthopsilosis isolates was able to produce phospholipase. Higher caseinase activities were detected in C. parapsilosis (Pz = 0.5 ± 0.18) and C. orthopsilosis (Pz = 0.49 ± 0.07) than in C. metapsilosis isolates (Pz = 0.72 ± 0.1). 96.5% of C. parapsilosis strains and all isolates of C. metapsilosis and C. orthopsilosis produced gelatinase. All the strains possessed the ability to show haemolysis on blood agar. C. metapsilosis exhibited the low haemolysin production with statistical significant differences compared to C. parapsilosis and C. orthopsilosis. The biofilm forming ability of C. parapsilosis was highly strain dependent with important heterogeneity, which was less evident with both C. orthopsilosis and C. metapsilosis. Some C. parapsilosis isolates met the criterion for susceptible dose dependent to fluconazole (10.91%), itraconazole (16.36%) and voriconazole (7.27%). Moreover, 5.45% and 1.82% of C. parapsilosis isolates were respectively resistant to fluconazole and voriconazole. All strains of C. metapsilosis and C. orthopsilosis were susceptible to azoles; and isolates of all three species exhibited 100% of susceptibility to caspofungin, amphotericin B and 5-flucytosine.
CONCLUSIONS
A combination of molecular mechanisms, including the overexpression of ERG11, and genes encoding efflux pumps (CDR1, MDR1, and MRR1) were involved in azole resistance in C. parapsilosis.
背景
本研究旨在确定假丝酵母复合种群中 182 株临床分离株的生物膜形成和细胞外酶活性。
方法
采用 SADH 基因 PCR-RFLP 和 ITS 区 PCR 测序对假丝酵母复合种群进行分子鉴定。评估了我们分离株对抗真菌药物的敏感性和唑类耐药的分子机制。
结果
63.5%的假丝酵母为磷脂酶阳性，大多数菌株的活性为中等。没有一株近平滑假丝酵母或中间假丝酵母能够产生磷脂酶。假丝酵母（Pz=0.5±0.18）和中间假丝酵母（Pz=0.49±0.07）的角蛋白酶活性高于近平滑假丝酵母（Pz=0.72±0.1）。96.5%的假丝酵母菌株和所有近平滑假丝酵母和中间假丝酵母的分离株均能产生明胶酶。所有菌株在血琼脂上均具有溶血能力。与假丝酵母和中间假丝酵母相比，近平滑假丝酵母的溶血素产量较低，差异具有统计学意义。假丝酵母的生物膜形成能力高度依赖于菌株，存在明显的异质性，而中间假丝酵母和近平滑假丝酵母的生物膜形成能力则不那么明显。一些假丝酵母分离株符合氟康唑（10.91%）、伊曲康唑（16.36%）和伏立康唑（7.27%）敏感剂量依赖性的标准。此外，假丝酵母分离株分别有 5.45%和 1.82%对氟康唑和伏立康唑耐药。所有中间假丝酵母和近平滑假丝酵母的分离株均对唑类药物敏感；三种菌的分离株对卡泊芬净、两性霉素 B 和 5-氟胞嘧啶的敏感性均为 100%。
结论
假丝酵母中唑类耐药涉及多种分子机制，包括 ERG11 过表达和外排泵（CDR1、MDR1 和 MRR1）编码基因。
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