Aim: An attempt to use MALDI-TOF mass-spectrometry method for identification of lep- tospiral isolates on the serovar level.
Materials and methods: 8 reference Leptospira spp. and 11 leptospira strains isolated from leptospiral patients and infected animals in the North-Western region of Russia were included into the study. Mass-spectra of all the studied strains were obtained by direct profiling of cell extracts. The created main spectral profiles (MSP) of reference strains were used for identification of isolates. Evaluation of identification was carried out by calculating coefficients of matching rate of separate spectra of each isolate with MSP of all the reference strains.
Results: Results of identification have shown the similarity of spectra of isolates belonging to Pomona, Icterohaemorrhagiae and Canicola serogroups, with MSP of saprophyte strain L. biflexa Patoc I. It is assumed that spectra of the studied strains contained peaks of polysaccha- ride Ο-antigens. Wherein maximum mean values of matching rate coefficients between spectra of isolates and MSP of pathogenic reference strains of leptospira correctly matched serovar type of the isolate.
Conclusion: Further extended studies may form the base of development of a simple and rapid method oftyping of leptospirosis causative agents on the level of serovars using MALDITOF mass-spectrometry.