Species identification of Aspergillus, Fusarium and Mucorales with direct surface analysis by matrix-assisted laser desorption ionization time-of-flight mass spectrometry
Species identification of Aspergillus, Fusarium and Mucorales with direct surface analysis by matrix-assisted laser desorption ionization time-of-flight mass spectrometry
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DOI：
10.1111/j.1469-0691.2011.03599.x
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发表时间：
2012-05-01
影响因子：
14.2
通讯作者：
Fadda, G.
中科院分区：
文献类型：
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作者：
De Carolis, E.;Posteraro, B.;Fadda, G.
准确的丝状真菌物种鉴别是必不可少的，因为一些物种具有特定的抗真菌药敏模式，错误的鉴定可能导致不适当的治疗。我们评估了基质辅助激光解吸电离飞行时间质谱（MALDI-TOF类似于MS）的物种鉴定，通过直接表面分析的真菌培养。通过使用代表曲霉属、镰刀菌属和毛霉目的55个种的培养物收集菌株，根据制造商对microflex测量的建议和类似于2.0软件的MALDI BioTyper，建立了类似于基于MS的种鉴定的MALDI-TOF参考数据库。年轻和成熟的菌落的配置文件进行了分析，为每个参考菌株，并获得物种特异性的光谱指纹。为了评价数据库，对常规临床微生物实验室收集的103株盲法编码真菌分离株进行了检测。作为种属命名的参考方法，使用了多位点测序。85株分离株被明确鉴定为种属水平（=99%序列相似性）;在该阈值下产生模糊结果的18株分离株最初仅被评定为属水平。进一步的分子分析明确指定这些分离株的菌种曲霉菌（17分离株）和黄曲霉菌（1分离株），与MALDI-TOF相似MS结果一致。排除9个菌株，属于真菌物种不包括在我们的参考数据库中，91（96.8%）的94个分离株被鉴定的MALDI-TOF类似MS的物种水平，与参考方法的结果一致; 3个分离株被鉴定到属的水平。结论：MALDI-TOF与MS相似，适用于医学微生物实验室丝状真菌的常规鉴定。
Accurate species discrimination of filamentous fungi is essential, because some species have specific antifungal susceptibility patterns, and misidentification may result in inappropriate therapy. We evaluated matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF similar to MS) for species identification through direct surface analysis of the fungal culture. By use of culture collection strains representing 55 species of Aspergillus, Fusarium and Mucorales, a reference database was established for MALDI-TOF similar to MS-based species identification according to the manufacturers recommendations for microflex measurements and MALDI BioTyper similar to 2.0 software. The profiles of young and mature colonies were analysed for each of the reference strains, and species-specific spectral fingerprints were obtained. To evaluate the database, 103 blind-coded fungal isolates collected in the routine clinical microbiology laboratory were tested. As a reference method for species designation, multilocus sequencing was used. Eighty-five isolates were unequivocally identified to the species level (=99% sequence similarity); 18 isolates producing ambiguous results at this threshold were initially rated as identified to the genus level only. Further molecular analysis definitively assigned these isolates to the species Aspergillus oryzae (17 isolates) and Aspergillus flavus (one isolate), concordant with the MALDI-TOF similar to MS results. Excluding nine isolates that belong to the fungal species not included in our reference database, 91 (96.8%) of 94 isolates were identified by MALDI-TOF similar to MS to the species level, in agreement with the results of the reference method; three isolates were identified to the genus level. In conclusion, MALDI-TOF similar to MS is suitable for the routine identification of filamentous fungi in a medical microbiology laboratory.