Application of MALDI mass spectrometry for species identification and intraspecific differentiation of dermatophyte Microsporum canis of anthroponotic and zoonotic origin

Microsporum canis is an important fungal pathogen that is mainly transmitted to humans from domestic animals. Different strains of M. canis vary in their ability to infect humans. Comparative studies of M. canis strains from humans and animals using MALDI mass spectrometry have not yet been published. In a comparative aspect, M. canis strains isolated from human (HS 09-18) and cat (FC 19-18) were studied. Comparison of the obtained mass spectra revealed that M. canis HS 09-18 displayed characteristic peaks with m/z 3339, 4287, 6485, 7740 and 8568, while M. canis FC 19-18 displayed unique peaks with m/z 5192, 7221 and 8049. Three peaks with maximum intensity with m/z 6112, 6828, 9625 were found in both M. canis strains. The dendrogram built on the basis of MALDI mass spectra revealed the clustering of M. canis strains in accordance with their origin: strains from cats and humans formed two separate clusters. Thus, clear differences were demonstrated between M. canis strains depending on the source of origin (cat and human). MALDI mass spectrometry makes it possible to carry out species identification, as well as to reveal intraspecific differences in M. canis. The mechanisms that allow dermatophytes to switch from zoophilic to anthropophilic behavior need to be further explored.