Maldi biotyper automation

Bacteria from pure cultures #2 and #4 were identified by Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF). The protein mass spectra were acquired with the use of an automated mass spectrometer Bruker MALDI-TOF BioTyper (Bruker Daltonics, Germany) within the range of m/z 3 000 to 15 000. The Bruker MALDI-TOF BioTyper target plate was inoculated with bacterial test standard (Bruker #8255343) and calibration was performed according to the recommendations of the manufacturer. Using the direct colony transfer method, the tested bacteria were applied to the target spot, allowed to dry and covered with 1 µl of 70% formic acid, followed by 1 µl of matrix (Bruker, HCCA #8255344). The bacterial identification was obtained using a Microflex LT instrument (Bruker Daltonics, Germany) with Flex Control (version 3.0) software (Bruker Daltonics, Germany). The mass spectra were matched with the spectral database carried out by automated software, the MALDI BioTyper automation (version 2.0) software (Bruker Daltonics, Germany). The identification was conducted by Clinical Microbiology, London Health Science Centre, London, Ontario.

Identification of the retained fractions by MALDI-TOF-MS was performed on a Microflex LT instrument (Bruker Daltonics GmbH, Leipzig, Germany) with FlexControl (version 3.0) software (Bruker Daltonics) for the automatic acquisition of mass spectra in the linear positive mode within a range of 2–20 kDa, according to the instructions of the manufacturer. Automated analysis of the raw spectral data was performed by the MALDI BioTyper automation (version 2.0) software (Bruker Daltonics) and the default settings. The lyophilized powder of retention fraction was overlaid with 1 μL of HCCA matrix (a saturated solution of α -cyano-4-hydroxycinnamic acid in 50% acetonitrile–2.5% trifluoroacetic acid) and air dried at room temperature to allow cocrystallization with the experimental sample. The spectra were then acquired by the mass spectrometer.