Trichophyton tonsurans produtor de clamidoconídios: análise sobre a taxonomia, perfil proteico, filogenia e sensibilidade de biofilmes

Abstract

In the state of Ceará, we have isolated strains of T. tonsurans with atypical morphological presentation, characterized by abundant production of chlamydoconidia. The objectives of this study were threefold: (i) to ascertain the protein and genetic profiles of T. tonsurans strains that produce chlamydoconidia; (ii) to investigate the capacity to form biofilms of these strains; and (iii) to observe the effect of terbinafine and farnesol on biofilms of this dermatophyte. We analyzed six strains of T. tonsurans that produce chlamydoconidia and one standard strain (ATCC 28942). The protein profile was investigated by MALDI-TOF MS. In the genetic analysis, the ITS and LSU loci regions of rDNA and the partial β-tubulin gene were amplified. The gene sequences were compared by the BLAST platform, the multiple alignment was obtained with MAFFT and the dendograms were plotted with MEGA X. The antifungal activity was evaluated by the broth microdilution method. The effects of terbinafine (2 to 128 µg/mL) and farnesol (18.75 to 1200 mM) on the biofilms of these strains were evaluated by quantifying the biomass and measuring the metabolic activity. The morphology of the biofilms was analyzed by scanning electron and confocal microscopies. In the strains of T. tonsurans that produce chlamydoconidia, intense protein peaks were observed with 4,155 Da and absence of proteins with 3,087 Da, 6,177 Da and 6,649 Da. From a phylogenetic standpoint, the strains could be allocated in a single cluster and were strong biofilm formers. Although these strains produced less biomass, their metabolic activity was comparable to that of the standard strain ATCC 28942. Terbinafine reduced the biomass by 66.22% and the metabolic activity by 69%, while farnesol reduced the biomass by as much as 65.15% and the metabolic activity of the biofilms by 68.43%. Terbinafine significantly reduced the biomass and metabolic activity of the biofilms starting at concentrations of 4 ug/mL and 2 ug/mL, respectively. In turn, farnesol significantly diminished the biomass and metabolic activity of the biofilms starting at respective concentrations of 300 mM and 18.75 mM. The conclusion is that T. tonsurans strains that produce chlamydoconidia have significant phenotypic alterations, with similar genotypic patterns and different protein profiles. Furthermore, terbinafine and farnesol presented similar action on the biomass and metabolic activity of the biofilms, indicating antifungal activity of farnesol against biofilms of T. tonsurans strains that produce chlamydoconidia.