Abstract
Antifungal drug resistance in
Candida
spp. continues to increase in response to the widespread application of triazole therapeutics among immunosuppressed patients. Azole-based over-the-counter (OTC)
antifungal agents used to treat vaginitis have the potential to exacerbate this problem by contributing to the selection of highly resistant strains of
Candida
in otherwise healthy women. In this
study, we show that fluconazole-resistant (MIC > 64 μg/mL) blood stream isolates of
Candida albicans
and
Candida glabrata
obtained from cancer patients were cross-resistant to the root
drugs miconazole, clotrimazole, and tioconazole (found in several over-the-counter products), but remained susceptible to butoconazole. We also provide evidence that spontaneous mutants of
Candida glabrata
selected for resistance to clotrimazole were cross-resistant to other azole-based drugs, including fluconazole. Our findings demonstrate cross-resistance of
Candida
strains to fluconazole and OTC
azole antifungals, and support the notion that OTC drugs can promote azole resistance in
Candida
spp.