Mbt compass software

After deposition of microbial biomass (the amount that adheres to a sterile toothpick tip) onto a polished steel MALDI target, 1 μl of 70% formic acid was added and allowed to dry. This was followed by overlaying with α-cyano-4-hydroxycinnamic acid matrix and MALDI-TOF MS measurement using the Microflex instrument (Bruker, Bremen, Germany) and MBT Compass software (version 4.1.80; Bruker). Time intervals for each solid medium were recorded until low-confidence identification (score of ≥1.7 to <2) and high-confidence identification (score of ≥2) were achieved. If a score of ≥2 was obtained, the respective colonies were not tested again at later time points.

All isolates were identified by MALDI-TOF MS using the Mass Spectrometry Identification 2 (MSI 2) platform database [16 ]. Fungal proteins were extracted from a mature subculture on Malt extract-agar medium (VWR, Rosny-Sous-Bois, France) using a previously described extraction protocol with minor modifications [17 (link)]. Briefly, a loop-full of mycelial colonies was transferred into a 1.5 mL microtube containing 300 μL of pure water and 900 μL of pure ethanol. After two centrifugations at 13,000× g for 2 min, the pellet was suspended in 25 μL of 70% formic acid and 25 μL of 100% acetonitrile. A sample of 1.0 μL of the fungal extract supernatant was spotted on a 96-spot polished steel plate in duplicate (Bruker Daltonics, Billerica, MA, USA) and allowed to completely dry at room temperature. Then, 1 μL of the IVD matrix HCCA portioned solution (Bruker Daltonik, Ref: 8290200, Billerica, MA, USA) was added. Protein spectra were analyzed using FlexControl^TM software with and the MBT compass software (Bruker, Billerica, MA, USA) and compared with Mass Spectrometry Identification (MSI) platform database 2. Identification was retained when the MSI score was above or equal to 20%. If several identification results were proposed for the same specimen, only the result with the best score was retained.