Background:CAY-1, a surface-active sapoinin in Capsicum spp. fruit, is highly lethal for Aspergillus spp., Candida albicans, and Pneumocystis carinii below 20 mmolar. To further characterize CAY-1, synergy studies with amphotericin B (AMB) and itraconazole (IT) were performed. Methods: Synergy was determined by the checkerboard microdilution method against nongerminated (NG) and germinating (G) conidia of Aspergillus fumigatus, A. niger, A. flavus, and Candida albicans on three separate occassions. Concentrations used were: 0-15.5 mg/ml (CAY-1) and 0.075-1.25 m (AMB, IT). Growth inhibition was observed at 24 and 48hrs and the Fractional Inhibitory Concentration Index (FICI) calculated. Results: FICI for CAY-1 and AMB against NG and G conidia of A. fumigatus at 0.78, 0.82, and 0.66, 0.74, respectively. CAY-1 with AMB against NG and G conidia of A. niger at 24 and 48 hrs had FICI of 0.81, 2.0, and 0.91, 0.99, respectively. FICI values of CAY-1 and AMB for NG and G conidia of A. flavus at 24 and 48 hrs 0.6, 2.0, and 1.5, 1.38, respectively. CAY-1 had FICI values with IT against NG and G conidia of A. fumigatus at 24 and 48 hrs of 0.89, 0.64, and 0.66, 0.86, respectively. CAY-1 and IT produced FICI values of 0.83, 0.66, and 0.83, 0.58 at 24 and 48 hrs, respectively, against NG and G conidia of A. niger. With CAY-1 and IT, results show indifferent synergy against A. flavus (FICI range: 0.88-2.00). Synergy was observed between CAY-1 and AMB at 24 and 48 hrs against C. albicans (FICI: 0.22 and 0.32, respectively), while CAY-1 and IT had indifferent synergy against C. albicans (FICI: 2.0). Conclusions: Overall, CAY-1 displayed additive synergy with AMB and IT against the Aspergillus spp. and good synergy with AMB against C. albicans. Results indicate CAY-1 may enhance the efficacy of azole and polyene antifungals.
Full conference title:
42nd Interscience Conference on Antimicrobial Agents and Chemotherapy
- ICAAC 42nd