Novel bacterial classification method by MALDI-TOF MS based on ribosomal protein coding in S10-spc-alpha Operon at Strain level

Although our previous study demonstrated the bacterial identification method at strain level based on ribosomal protein matching profiling by comparison between the observed masses in the MALDI mass spectra of sample strains and the biomarker masses of the reference strain, there is one disadvantage in making phylogenetic classification. Ribosomal protein database of type strains which are important for the identification of bacterial species is not incomplete because many of these species are not genome sequenced.

Therefore, we developed a novel bacterial classification method by MALDI-TOF MS using ribosomal subunit proteins coded in S10-spc-alpha operon as biomarkers, because the operon encodes half of the ribosomal subunit and can be easily sequenced using conventional DNA sequencer.

We have already reported that our proposed method could successfully distinguish the difference at strain level because of mass difference of 2 ribosomal subunit proteins, despite the difference of only 2 bases in the 16S rRNA gene between two strains of genus Bacillus. Now we are trying to differentiate other bacterial species which are difficult to discriminate using the mass fingerprinting method. These bacterial species under our evaluation are important in the area of food safety so we expect that our trial will contribute to this area.