RESUMO
AIMS: To evaluate the antimicrobial activity and to determine the pharmacodynamic characteristics of three 8-hydroxyquinoline derivatives (8-HQs) against Pythium insidiosum, the causative agent of pythiosis. METHODS AND RESULTS: Antimicrobial activity was tested by broth microdilution and MTT assays. The antimicrobial mode of action was investigated using sorbitol protection assay, ergosterol binding assay, and scanning electron microscopy. Clioquinol, PH151, and PH153 were active against all isolates, with MIC values ranging from 0.25 to 2 µg ml-1. They also showed a time- and dose-dependent antimicrobial effect, damaging the P. insidiosum cell wall. CONCLUSIONS: Together, these results reinforce the potential of 8-HQs for developing new drugs to treat pythiosis.
RESUMO
In this study, we investigate the ability of Pythium insidiosum to form biofilms across various substrates and the antibiofilm efficacy of 8-hydroxyquinoline derivatives (8-HQs). Biofilms of P. insidiosum were cultured on polystyrene plates, contact lenses, and horsehair. We provide the first evidence of P. insidiosum's biofilm-forming capability, thus considerably expanding our understanding of its transmission and pathogenesis. Our results demonstrate that 8-HQs effectively inhibit biofilm formation and eradicate pre-existing biofilms, underscoring their potential as a novel treatment strategy for pythiosis, a disease currently lacking a gold-standard treatment. This finding has particular relevance for ocular pythiosis associated with contact lens usage and potential infection sources in animals. Our results contribute to the scientific knowledge base and directly impact innovative therapeutic interventions' development.