Clioquinol and 8-hydroxyquinoline-5-sulfonamide derivatives damage the cell wall of Pythium insidiosum

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 mu g 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.

Automated summary

This study evaluates the antimicrobial activity of three 8-hydroxyquinoline derivatives against Pythium insidiosum and determines their pharmacodynamic characteristics. Results show that Clioquinol, PH151, and PH153 are active against all isolates, with MIC values ranging from 0.25 to 2 μg/mL. They also exhibit a time- and dose-dependent antimicrobial effect, damaging the P. insidiosum cell wall. These findings reinforce the potential of 8-hydroxyquinoline derivatives as new drugs for treating pythiosis.