Zvezdanova M E, Escribano P, Ruiz A, Martínez-Jiménez M C, Peláez T, Collazos A, Guinea J, Bouza E, Rodríguez-Sánchez B
Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
Med Mycol. 2019 Jan 1;57(1):63-70. doi: 10.1093/mmy/myx154.
In this study we evaluated the capacity of MALDI-TOF MS (Bruker Daltonics, Bremen, Germany) to identify clinical mould isolates. We focused on two aspects of MALDI-TOF MS identification: the sample processing and the database. Direct smearing of the sample was compared with a simplified processing consisting of mechanical lysis of the moulds followed by a protein extraction step. Both methods were applied to all isolates and the Filamentous Fungi Library 1.0 (Bruker Daltonics) was used for their identification. This approach allowed the correct species-level identification of 25/34 Fusarium spp. and 10/10 Mucor circinelloides isolates using the simplified sample processing. In addition, 7/34 Fusarium spp. and 1/21 Pseudallescheria/Scedosporium spp. isolates were correctly identified at the genus level. The remaining isolates-60-could not be identified using the commercial database, mainly because of the low number of references for some species and the absence of others. Thus, an in-house library was built with 63 local isolates previously characterized using DNA sequence analysis. Its implementation allowed the accurate identification at the species level of 94 isolates (91.3%) and the remaining nine isolates (8.7%) were correctly identified at the genus level. No misidentifications at genus level were detected. In conclusion, with improvements of both the sample preparation and the feeding of the database, MALDI-TOF MS is a reliable, ready to use method to identify moulds of clinical origin in an accurate, rapid, and cost-effective manner.
在本研究中，我们评估了基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS，布鲁克道尔顿公司，德国不来梅）鉴定临床霉菌分离株的能力。我们聚焦于MALDI-TOF MS鉴定的两个方面：样本处理和数据库。将样本直接涂片与一种简化处理方法进行比较，简化处理方法包括对霉菌进行机械裂解，随后进行蛋白质提取步骤。两种方法均应用于所有分离株，并使用丝状真菌库1.0（布鲁克道尔顿公司）进行鉴定。采用简化样本处理方法，这种方法能够正确鉴定出25/34株镰刀菌属菌株和10/10株卷枝毛霉分离株的物种水平。此外，7/34株镰刀菌属菌株和1/21株拟阿利什霉/帚霉属菌株在属水平上被正确鉴定。其余60株分离株无法使用商业数据库进行鉴定，主要原因是某些物种的参考序列数量较少以及其他物种序列缺失。因此，利用先前通过DNA序列分析鉴定的63株本地分离株构建了一个内部文库。该文库的应用使得94株分离株（91.3%）在物种水平上得到准确鉴定，其余9株分离株（8.7%）在属水平上被正确鉴定。未检测到属水平的错误鉴定。总之，通过改进样本制备和数据库输入，MALDI-TOF MS是一种可靠、易于使用的方法，能够以准确、快速且经济高效的方式鉴定临床来源的霉菌。
