Normand A C, Becker P, Gabriel F, Cassagne C, Accoceberry I, Gari-Toussaint M, Hasseine L, De Geyter D, Pierard D, Surmont I, Djenad F, Donnadieu J L, Piarroux M, Ranque S, Hendrickx M, Piarroux R
Laboratoire de Parasitologie-Mycologie, CHU Timone, Aix-Marseille Université, Marseille, France
Service of Mycology and Aerobiology, BCCM/IHEM Fungal Collection, Scientific Institute of Public Health, Brussels, Belgium.
J Clin Microbiol. 2017 Sep;55(9):2661-2670. doi: 10.1128/JCM.00263-17. Epub 2017 Jun 21.
Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry has emerged as a reliable technique to identify molds involved in human diseases, including dermatophytes, provided that exhaustive reference databases are available. This study assessed an online identification application based on original algorithms and an extensive in-house reference database comprising 11,851 spectra (938 fungal species and 246 fungal genera). Validation criteria were established using an initial panel of 422 molds, including dermatophytes, previously identified via DNA sequencing (126 species). The application was further assessed using a separate panel of 501 cultured clinical isolates (88 mold taxa including dermatophytes) derived from five hospital laboratories. A total of 438 (87.35%) isolates were correctly identified at the species level, while 26 (5.22%) were assigned to the correct genus but the wrong species and 37 (7.43%) were not identified, since the defined threshold of 20 was not reached. The use of the Bruker Daltonics database included in the MALDI Biotyper software resulted in a much higher rate of unidentified isolates (39.76 and 74.30% using the score thresholds 1.7 and 2.0, respectively). Moreover, the identification delay of the online application remained compatible with real-time online queries (0.15 s per spectrum), and the application was faster than identifications using the MALDI Biotyper software. This is the first study to assess an online identification system based on MALDI-TOF spectrum analysis. We have successfully applied this approach to identify molds, including dermatophytes, for which diversity is insufficiently represented in commercial databases. This free-access application is available to medical mycologists to improve fungal identification.
基质辅助激光解吸电离飞行时间（MALDI-TOF）质谱已成为一种可靠的技术，可用于鉴定涉及人类疾病的霉菌，包括皮肤癣菌，前提是有详尽的参考数据库。本研究评估了一种基于原始算法的在线鉴定应用程序以及一个包含11,851个光谱（938种真菌和246个真菌属）的广泛内部参考数据库。使用最初一组422株霉菌（包括先前通过DNA测序鉴定的126种皮肤癣菌）建立验证标准。使用来自五个医院实验室的另一组501株培养临床分离株（包括88个霉菌分类单元，其中有皮肤癣菌）进一步评估该应用程序。共有438株（87.35%）分离株在种水平上被正确鉴定，26株（5.22%）被归为正确的属但种错误，37株（7.43%）未被鉴定，因为未达到定义的20分阈值。使用MALDI Biotyper软件中包含的布鲁克道尔顿公司数据库导致未鉴定分离株的比例高得多（分别使用得分阈值1.7和2.0时，未鉴定率为39.76%和74.30%）。此外，在线应用程序的鉴定延迟与实时在线查询兼容（每个光谱0.15秒），并且该应用程序比使用MALDI Biotyper软件进行鉴定更快。这是第一项评估基于MALDI-TOF光谱分析的在线鉴定系统的研究。我们已成功应用此方法鉴定霉菌，包括皮肤癣菌，而商业数据库中对其多样性的代表性不足。该免费访问应用程序可供医学真菌学家使用，以改进真菌鉴定。
