Retrospective observation of drug susceptibility of Candida strains in the years 1999, 2004, and 2015

INTRODUCTION: There is much literature devoted to the problem of drug resistance and decreased susceptibility of fungi to commonly used antifungals. AIM: To analyze drug susceptibility of Candida albicans and non-Candida albicans strains isolated from the hands of people without any symptoms of disease over a 16-year period. MATERIALS AND METHODS: The study included a total of 1,274 Candida-type strains isolated from the hands of people without any symptoms of disease, including: in 1999, 432 strains; in 2004, 368; and in 2015, 454 strains. Biological monitoring of hand surface contamination was performed using the Count-Tact(TM) applicator with Count-Tact plates (bioMerieux). Drug susceptibility was evaluated using FUNGITEST(®). RESULTS: In 1999, the most strains showed resistance to fluconazole (53.2%), in 2004 to itraconazole (52.9%), and in 2015 to fluconazole (85.8%). Resistance to more than one drug was 35.8% in 1999, 64.7% in 2004, and 92% in 2015. Mean resistance to azole antifungals significantly increased from 98 ± 39.7 strains in 1999 to 118.3 ± 29.6 in 2015 (p < 0.001). In 1999, the most strains showed resistance to fluconazole (50.6%), in 2004 to itraconazole (52.9%), and in 2015 to fluconazole (44.9%). Resistance to more than one drug was 52.9% in 1999, 64.3% in 2004, and 88.1% in 2015. Mean resistance to azole antifungals significantly increased from a mean of 76 ± 9.7 strains in 1999, to 95.3 ± 24.2 in 2004, and to 97.3 ± 16.6 in 2015 (p < 0.001). CONCLUSIONS: We showed increased C. albicans and non-Candida albicans strain resistance to commonly used antifungal chemotherapeutics, mainly imidazole. We found a clear rise in susceptibility of C. albicans and non-Candida albicans strains to several studied antifungals.