Hou Xin, Xiao Meng, Chen Sharon C-A, Wang He, Yu Shu-Ying, Fan Xin, Kong Fanrong, Xu Ying-Chun
Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical SciencesBeijing, China; Graduate School, Peking Union Medical College, Chinese Academy of Medical SciencesBeijing, China.
Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences Beijing, China.
Front Microbiol. 2017 Jan 19;8:5. doi: 10.3389/fmicb.2017.00005. eCollection 2017.
and are two emerging cryptic species within the complex. Thirteen of these isolates from 10 hospitals in China were studied for their species identification and antifungal susceptibilities. Phenotypic and molecular [rDNA ITS sequencing, D1/D2 sequencing and ITS sequencer-based capillary gel electrophoresis (SCGE)] and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) MS identification methods were compared for their performance in species identification. Twelve of 13 (92.3%) isolates were identified as and one as using ITS sequencing as the reference method. Results obtained by D1/D2 sequencing and ITS SCGE were concordant with ITS sequencing results for all (100%) isolates. SCGE was able to subtype 12 into four ITS SCGE length types. All isolates failed to be identified by the Vitek MALDI-TOF MS system (bioMérieux), whilst the Bruker MS system (Bruker Daltoniks) correctly identified all isolates but using a lowered (≥1.700) cut-off score for species assignment; the isolate was identified but with score <1.700. The Vitek 2 Compact system could not identify 11 and one isolate and misidentified the remaining strain as "" All isolates were susceptible-dose dependent to fluconazole [minimum inhibitory concentration (MIC) range 0.5-4 μg/mL] and were classed as susceptible to echinocandins (MICs ≤ 0.06 μg/mL). All 13 isolates had low MICs for other azoles (MICs ≤ 0.5 μg/mL), amphotericin B (MICs ≤ 2 μg/mL) and 5-flucytosine (MICs ≤ 0.25 μg/mL). Our results reinforce the need for molecular differentiation of species of and . The performance of MALDI-TOF may be improved by adding mass spectral profiles (MSPs) into the current databases. The antifungal susceptibility profile of isolates should be monitored.
和是复合体中两个新出现的隐性物种。对来自中国10家医院的13株此类分离株进行了物种鉴定和抗真菌药敏试验。比较了表型和分子[rDNA ITS测序、D1/D2测序以及基于ITS测序仪的毛细管凝胶电泳（SCGE）]和基质辅助激光解吸电离飞行时间（MALDI-TOF）质谱鉴定方法在物种鉴定中的性能。以ITS测序作为参考方法，13株分离株中有12株（92.3%）被鉴定为，1株被鉴定为。D1/D2测序和ITS SCGE获得的结果与所有（100%）分离株的ITS测序结果一致。SCGE能够将12株分为四种ITS SCGE长度类型。Vitek MALDI-TOF MS系统（生物梅里埃公司）未能鉴定出所有分离株，而布鲁克质谱系统（布鲁克道尔顿公司）正确鉴定出所有分离株，但在物种分类时使用了较低（≥1.700）的截断分数；该分离株被鉴定出来，但分数<1.700。Vitek 2 Compact系统无法鉴定11株和1株分离株，并将其余1株菌株错误鉴定为“”。所有分离株对氟康唑呈剂量依赖性敏感[最低抑菌浓度（MIC）范围为0.5-4μg/mL]，对棘白菌素类药物敏感（MIC≤0.06μg/mL）。所有13株分离株对其他唑类药物（MIC≤0.5μg/mL）、两性霉素B（MIC≤2μg/mL）和5-氟胞嘧啶（MIC≤0.25μg/mL）的MIC值均较低。我们的结果强化了对和进行物种分子鉴别研究的必要性。通过在当前数据库中添加质谱图谱（MSP），可能会提高MALDI-TOF的性能。应监测分离株的抗真菌药敏谱。
