In vitro susceptibility profile of 200 recent clinical isolates of Candida spp. to topical antifungal treatments of vulvovaginal candidiasis, the imidazoles and nystatin agents

Abstract

Objective: Topical antifungal treatment of vulvovaginal candidiasis is widely recommended. The most commonly recommended topical antifungals (the imidazoles clotrimazole, miconazole and econazole and the polyene nystatin) have been on the market for more than 30 years. There are only a few recent data available on the susceptibility of different Candida species to these antifungals, especially of non-albicans Candida species which appear to be less responsive to treatment with imidazoles. The study aimed to determine the in vitro susceptibility profile of a large number of recent clinical isolates of Candida spp. to the most commonly recommended topical antifungals.

Materials and methods: An antifungal susceptibility test was performed according to the CLSI M27-A3 broth microdilution method, and minimal inhibitory concentrations were determined for econazole, miconazole, clotrimazole and nystatin.

Results: The clinical isolates comprised of: 113 Candida albicans, 54 Candida glabrata, 11 Candida krusei, 11 Candida tropicalis and 11 Candida parapsilosis. The three azoles agents exhibited MIC90 values of 0.06 mg/L against C. albicans isolates, while nystatin exhibited a MIC90 of 4 mg/L. For non-albicans Candida isolates, MIC90 values ranged from 0.5 to 8 mg/L, from 1 to 4 mg/L and from 0.12 to 4 mg/L, for econazole, miconazole, clotrimazole, respectively. Nystatin MIC90 remained at 4 mg/L for all non-albicans Candida species tested.

Conclusion: These results confirmed the susceptibility of C. albicans to the most frequently used topical agents and may support the use of alternative agents to imidazoles, such as nystatin, to treat vulvovaginal candidiasis caused by non-albicans Candida species.

Keywords: Broth microdilution; Candida sp.; Candida spp.; Candidose vulvovaginale; Concentration minimale inhibitrice; Imidazolés topiques; Microdilution; Minimal inhibitory concentration; Nystatin; Nystatine; Topical imidazole agents; Vulvovaginal candidiasis.