Inhibitory effect of proteinase K against dermatophyte biofilms: an alternative for increasing the antifungal effects of terbinafine and griseofulvin

• Published in: Biofouling (Chur, Switzerland) Switzerland), 2022-03, Vol.38 (3), p.286-297
• Main Authors: Brilhante, Raimunda Sâmia Nogueira, Lopes, Raissa Geovanna Pereira, de Aguiar, Lara, de Oliveira, Jonathas Sales, Araújo, Géssica dos Santos, Paixão, Germana Costa, Pereira-Neto, Waldemiro de Aquino, Freire, Rosemayre Souza, Nunes, João Victor Serra, de Lima, Renan Pereira, Santos, Flávia Almeida, Sidrim, José Júlio Costa, Rocha, Marcos Fábio Gadelha
• Format: Article
• Language: English
• Subjects: antifungals; biofilm; Dermatophytes; proteinase K; synergism
• ISSN: 0892-7014; 1029-2454
• DOI: 10.1080/08927014.2022.2063720

This study aimed to evaluate the effect of proteinase K on mature biofilms of dermatophytes, by assays of metabolic activity and biomass. In addition, the proteinase K-terbinafine and proteinase K-griseofulvin interactions against these biofilms were investigated by the checkerboard assay and scanning electron and confocal microscopy. The biofilms exposed to 32 µg ml −1 of proteinase K had lower metabolic activity and biomass, by 39% and 38%, respectively. Drug interactions were synergistic, with proteinase K reducing the minimum inhibitory concentration of antifungals against dermatophyte biofilms at a concentration of 32 µg ml −1 combined with 128-256 µg ml −1 of terbinafine and griseofulvin. Microscopic images showed a reduction in biofilms exposed to proteinase K, proteinase K-terbinafine and proteinase K-griseofulvin combinations. These findings demonstrate that proteinase K has activity against biofilms of dermatophytes, and the interactions of proteinase K with terbinafine and griseofulvin improve the activity of drugs against mature dermatophyte biofilms.