Synergistic Activity of Minocycline and Rifampin in Combination with Antifungal Drugs against Candida auris

Candida auris is an emerging multidrug-resistant fungal pathogen that spreads readily in healthcare settings and has caused numerous hospital outbreaks. Very few treatment options exist for C. auris infections. We evaluated the activity of all two-drug combinations of three antifungal agents (amphotericin B, caspofungin, and voriconazole) and two antibacterial agents (minocycline and rifampin) against a collection of 10 C. auris isolates using an automated, inkjet printer-assisted checkerboard array method. Three antibacterial-antifungal combinations (amphotericin B plus rifampin, amphotericin B plus minocycline, and caspofungin plus minocycline) demonstrated synergistic activity by checkerboard array against [≥]90% of strains. The two amphotericin B-containing combinations were also synergistic using the time-kill synergy testing method. Our results suggest that combinations of antifungal and antibacterial agents may provide a promising avenue for treatment of this multidrug-resistant pathogen.