Department of Laboratory Medicine, General Hospital Maria Middelares, Ghent, Belgium.
Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium.
Med Mycol. 2020 Oct 1;58(7):946-957. doi: 10.1093/mmy/myz138.
During the last decade, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has revolutionized the diagnosis of fungal infections. Recently, a new Conidia ID-fungi plate (IDFP) medium was introduced to facilitate growth and sampling of fungi. This study aimed to evaluate the IDFP for fungal MALDI-TOF MS identification by comparison with a standard fungal growth medium using two reference libraries. A total of 75 filamentous fungal isolates (including 32 dermatophytes) were inoculated on IDFP and Sabouraud-gentamicin-chloramphenicol (SGC) agar and identified by MALDI-TOF MS using formic acid/acetonitrile extraction. Both the commercially available Bruker library (version 2.0) and the public available MSI web application (version 2018) were applied. For 15% of the isolates, a faster growth was noticed on IDFP compared to SGC. IDFP enhanced the performance of fungal identification compared to SGC for both MSI (increase of 16% identifications to genus and 5% to species level) and Bruker library (increase of 22% identifications to genus and 8% to species level). In total, only 73% of the tested isolates were present in the Bruker library compared to 92% for MSI library. No significant difference (P = 0.46) in MALDI score between IDFP and SGC was observed for the MSI library, but scores were significantly (P = 0.03) higher for IDFP when using Bruker library, potentially explained by the prevention of agar contamination by using IDFP since the Bruker database was created from liquid media. IDFP is a promising alternative growth medium for MALDI-TOF MS fungal identification which would strongly benefit from optimizing the Bruker reference library.
在过去的十年中，基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）技术彻底改变了真菌感染的诊断。最近，一种新的 Conidia ID-fungi 板（IDFP）培养基被引入，以促进真菌的生长和采样。本研究旨在通过使用两个参考库，比较 IDFP 与标准真菌生长培养基，评估 IDFP 对真菌 MALDI-TOF MS 鉴定的适用性。共接种了 75 株丝状真菌分离株（包括 32 株皮肤真菌）在 IDFP 和沙保弱葡萄糖琼脂（SGC）琼脂上，并使用甲酸/乙腈提取液通过 MALDI-TOF MS 进行鉴定。分别使用了市售的 Bruker 库（版本 2.0）和公共的 MSI 网络应用程序（版本 2018）。对于 15%的分离株，IDFP 上的生长速度比 SGC 快。与 SGC 相比，IDFP 提高了真菌鉴定的性能，在 MSI（属鉴定增加了 16%，种鉴定增加了 5%）和 Bruker 库（属鉴定增加了 22%，种鉴定增加了 8%）中均有提升。在 Bruker 库中，仅 73%的测试分离株与 MSI 库中 92%的分离株存在。MSI 库中，IDFP 和 SGC 的 MALDI 评分之间无显著差异（P=0.46），但使用 Bruker 库时，IDFP 的评分显著更高（P=0.03），这可能是由于 IDFP 防止了琼脂污染，因为 Bruker 数据库是从液体培养基中创建的。IDFP 是一种很有前途的 MALDI-TOF MS 真菌鉴定替代生长培养基，强烈需要优化 Bruker 参考库。
