Pence M A, McElvania TeKippe E, Wallace M A, Burnham C-A D
Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, 660 S. Euclid Ave., Campus Box 8118, St. Louis, MO, 63110, USA.
Eur J Clin Microbiol Infect Dis. 2014 Oct;33(10):1703-12. doi: 10.1007/s10096-014-2115-x. Epub 2014 May 7.
The rapid identification of yeast is essential for the optimization of antifungal therapy. The objective of our study was to evaluate two matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platforms, the bioMérieux VITEK MS (IVD Knowledgebase v.2.0) and Bruker Biotyper (software version 3.1), for the rapid identification of medically relevant yeast. One hundred and seventeen isolates, representing six genera and 18 species, were analyzed using multiple direct smear methods to optimize identification. Sequence analysis was the gold standard for comparison. Isolates were analyzed with VITEK MS using the direct smear method +/- a 25 % formic acid on-plate extraction. For Biotyper, isolates were analyzed using direct smear without formic acid, and with 25 % and 100 % formic acid on-plate extractions. When all methods were included, VITEK MS correctly identified 113 (96.6 %) isolates after 24 h with one misidentification, and Biotyper correctly identified 77 (65.8 %) isolates using a threshold of ≥2.0 with no misidentifications. Using a revised threshold of ≥1.7, Biotyper correctly identified 103 (88.0 %) isolates, with 3 (2.6 %) misidentifications. For both platforms, the number of identifications was significantly increased using a formic acid overlay (VITEK MS, p < 0.01; Biotyper, p < 0.001), and reducing the Biotyper threshold from ≥2.0 to ≥1.7 significantly increased the rate of identification (p < 0.001). The data in this study demonstrate that the direct smear method with on-plate formic acid extraction can be used for yeast identification on both MS platforms, and more isolates are identified using the VITEK MS system (p < 0.01).
快速鉴定酵母菌对于优化抗真菌治疗至关重要。我们研究的目的是评估两种基质辅助激光解吸/电离飞行时间质谱(MALDI-TOF MS)平台,即生物梅里埃VITEK MS(IVD知识库v.2.0)和布鲁克Biotyper(软件版本3.1),用于快速鉴定医学相关酵母菌。使用多种直接涂片方法对代表6个属和18个种的117株分离株进行分析以优化鉴定。序列分析是用于比较的金标准。使用直接涂片方法+/- 25%甲酸板上萃取对分离株进行VITEK MS分析。对于Biotyper,使用无甲酸的直接涂片以及25%和100%甲酸板上萃取对分离株进行分析。当纳入所有方法时,VITEK MS在24小时后正确鉴定了113株(96.6%)分离株,有1例假阳性,而Biotyper使用≥2.0的阈值正确鉴定了77株(65.8%)分离株,无假阳性。使用≥1.7的修订阈值,Biotyper正确鉴定了103株(88.0%)分离株,有3株(2.6%)假阳性。对于这两个平台,使用甲酸覆盖可显著增加鉴定数量(VITEK MS,p <0.01;Biotyper,p <0.001),并且将Biotyper阈值从≥2.0降低到≥1.7可显著提高鉴定率(p <0.001)。本研究中的数据表明,板上甲酸萃取的直接涂片方法可用于两个MS平台上的酵母菌鉴定,并且使用VITEK MS系统鉴定出更多分离株(p <0.01)。