engleski

Identification of urinary pathogens using MALDI- TOF/TOF instrument and peptide de novo sequencing

Mass spectrometry proteomic analysis of microorganisms is currently a routinely applied method for the identification of urinary tract pathogens. However, the method requires a lengthy culture step for sample preparation and is limited by 3329 available species in spectral libraries [1]. Herein, we propose the urinary tract pathogen identification method which overcomes the named limitations by utilization of the MALDI-TOF/TOF instrument [2]. Peptide sequences are elucidated de novo from tandem mass spectra by chemically activated fragmentation which allows mass spectrometry analysis in negative and positive ion modes. Later on, peptides sequences are matched against the National Centre for Biotechnology Information (NCBI) non-redundant database. For the purpose of data analysis, we have developed a specialized software package that provides a peptide sequence from the MS/MS negative and positive spectrum. The main advantage of this method compared to conventional MALDI-TOF is pathogen identification under 24 hours without cultivation step. Furthermore, the NCBI database used in the method consists of protein sequences derived by genome sequencing that currently holds 20917 bacterial species and constantly expanding [1]. Used method correctly identified uropathogens grown on agar plates as well as pathogens isolated directly from urine samples

Mass spectrometry ; proteomic analysis ; MALDI-TOF/TOF ; pathogen identification

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