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Oxythiamine improves antifungal activity of ketoconazole evaluated in canine Malassezia pachydermatis strains
Author(s) -
Siemieniuk Magdalena,
Sosnowska Katarzyna,
Czerniecki Jan,
Czyzewska Urszula,
Winnicka Katarzyna,
Tylicki Adam
Publication year - 2018
Publication title -
veterinary dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.744
H-Index - 60
eISSN - 1365-3164
pISSN - 0959-4493
DOI - 10.1111/vde.12688
Subject(s) - ketoconazole , malassezia , antifungal , minimum inhibitory concentration , microbiology and biotechnology , antifungal drugs , antifungal drug , biology , chemistry , antimicrobial
Background Malassezia pachydermatis is an opportunistic yeast involved in skin and ear canal infections of dogs and cats. Reports suggest that strains of M. pachydermatis resistant to commonly used antifungal agents may be emerging. Therefore, new therapeutic strategies should be explored. Objectives The synergistic effect of oxythiamine ( OT ) and ketoconazole ( KTC ) was analysed using a reference strain and field isolates (n = 66) of M. pachydermatis . Hydrogel formulations containing these components also were evaluated. Methods and materials The minimum inhibitory concentrations ( MIC s) and minimum fungicidal concentrations ( MFC s) of OT , KTC and their mixtures were determined by a broth macrodilution method. The antifungal effects of hydrogel formulations were determined by a plate diffusion method. Results The MIC and MFC values of OT were in the range 0.08 × 10 3 to 10 × 10 3 mg/L. All M. pachydermati s strains showed higher susceptibility to KTC ( MIC s and MFC s in the range 0.04–0.32 mg/L). Formulations that combined OT and KTC showed a synergistic effect for all tested isolates (n = 66). Hydrogels that contained OT at a concentration of 10 × 10 3 or 20 × 10 3 mg/L and KTC at the concentration of 0.1 × 10 3 mg/L showed a stronger effect than a commercially available product with KTC alone (20 × 10 3 mg/L). Conclusions and clinical importance Synergy of these drugs may allow for successful topical treatment which utilizes lower doses of KTC without changing its therapeutic effectiveness. Hydrogel formulations proved to be attractive drug carriers for potential topical use.