Evaluation of MALDI-TOF mass-spectrometry for the identification of clinical fungi MALDI-TOF MS Evaluierung zur Identifizierung klinischer Pilz-Isolate

Objectives: Candida, Cryptococcus and other fungi are responsible for several systemic diseases such as fungaemia, meningoencephalitis, peritonitis and pneumonia. Conventional identification of these organisms is not always simple and reliable. Retesting and morphological examination can be necessary. On the other hand, due to different anti-fungal profiles, rapid presumptive species identification is essential. Matrix-Assisted Laser-Desorption/Ionisation Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) is becoming a popular method for rapid identification of microorganisms. We compared the performance of this technique with conventional biochemical/physiological identification. Methods: A total of 290 clinical isolates of yeasts, yeast like organisms and other fungi on Sabouraud agar were analysed by MALDI-TOF MS. For sample preparation, a yeast conlony was transferred into 300 µl of water, suspended and mixed with 900 µl of ethanol. After centrifugation the pellet was resuspended in 35 % formic acid/50% acetonitrile and centrifuged. 1µl of the supernatant was used for measurement with α-cyano-4-hydroxy cinnamic acid matrix (Microflex LT, Bruker Daltonics, Germany). Bioinformatics was performed with the