McGill IR Group, McGill University, Sainte-Anne-de-Bellevue, Québec, Canada.
Institut National de Santé Publique du Québec, Laboratoire de Santé Publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada.
J Clin Microbiol. 2019 Apr 26;57(5). doi: 10.1128/JCM.01739-18. Print 2019 May.
Invasive fungal infections by opportunistic yeasts have increased concomitantly with the growth of an immunocompromised patient population. Misidentification of yeasts can lead to inappropriate antifungal treatment and complications. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy is a promising method for rapid and accurate identification of microorganisms. ATR-FTIR spectroscopy is a standalone, inexpensive, reagent-free technique that provides results within minutes after initial culture. In this study, a comprehensive spectral reference database of 65 clinically relevant yeast species was constructed and tested prospectively on spectra recorded (from colonies taken from culture plates) for 318 routine yeasts isolated from various body fluids and specimens received from 38 microbiology laboratories over a 4-month period in our clinical laboratory. ATR-FTIR spectroscopy attained comparable identification performance with matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). In a preliminary validation of the ATR-FTIR method, correct identification rates of 100% and 95.6% at the genus and species levels, respectively, were achieved, with 3.5% unidentified and 0.9% misidentified. By expanding the number of spectra in the spectral reference database for species for which isolates could not be identified or had been misidentified, we were able to improve identification at the species level to 99.7%. Thus, ATR-FTIR spectroscopy provides a new standalone method that can rival MALDI-TOF MS for the accurate identification of a broad range of medically important yeasts. The simplicity of the ATR-FTIR spectroscopy workflow favors its use in clinical laboratories for timely and low-cost identification of life-threatening yeast strains for appropriate treatment.
机会性酵母引起的侵袭性真菌感染随着免疫功能低下患者人群的增长而增加。酵母的错误鉴定可能导致不适当的抗真菌治疗和并发症。衰减全反射傅里叶变换红外（ATR-FTIR）光谱是一种快速准确鉴定微生物的有前途的方法。ATR-FTIR 光谱是一种独立的、廉价的、无试剂的技术，在初始培养后几分钟内即可提供结果。在这项研究中，构建了一个包含 65 种临床相关酵母物种的综合光谱参考数据库，并在 4 个月的时间里，前瞻性地对 318 种从各种体液和标本中分离出来的常规酵母的光谱进行了测试，这些标本来自 38 个微生物学实验室。ATR-FTIR 光谱与基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）具有相当的鉴定性能。在 ATR-FTIR 方法的初步验证中，在属和种水平上分别实现了 100%和 95.6%的正确鉴定率，未鉴定的比例为 3.5%，误鉴定的比例为 0.9%。通过扩展无法鉴定或鉴定错误的物种的光谱参考数据库中的光谱数量，我们能够将物种水平的鉴定率提高到 99.7%。因此，ATR-FTIR 光谱提供了一种新的独立方法，可以与 MALDI-TOF MS 相媲美，用于准确鉴定广泛的重要医学酵母。ATR-FTIR 光谱工作流程的简单性有利于其在临床实验室中用于及时、低成本地鉴定危及生命的酵母菌株，以进行适当的治疗。
