In vitro interaction of antifungal and antibacterial drugs against Cryptococcus neoformans var. grubii before and after capsular induction

This study evaluated the synergistic interactions between amphotericin B (AMB) and azithromycin (AZM), daptomycin (DAP), linezolid (LNZ), minocycline (MINO), fluconazole (FLZ), flucytosine (5FC), linezolid (LZD), or tigecycline (TIG) against clinical isolates of Cryptococcus neoformans var. grubii before and after capsule induction. High synergism (> 75%) was observed for the combinations, AMB+ 5FC, AMB+ TIG, AMB+ AZM, AMB+ LZD and AMB+ MINO but only in the strains after capsule induction. The results show that the presence of the capsule may lower theminimum inhibitory concentrations (MICs) of antifungal agents, but antimicrobial activity can be improved by combining antifungal and antibacterial agents.