Increasing rate of non-Candida albicans yeasts and fluconazole resistance in yeast isolates from women with recurrent vulvovaginal candidiasis in Leeds, United Kingdom

Abstract

Objectives Azoles have been the mainstay of recurrent vulvovaginal candidiasis (RVVC) for many years. Because of a recent anecdotal increase in non-Candida albicans yeasts (NCAY) and azole-resistant C. albicans cases, their prevalence was calculated from cultures for yeasts in women with complicated/RVVC over 3 years. Methods Retrospective data search of vaginal cultures from adult women in Leeds, UK between April 2018 and March 2021 was conducted. Samples with clinical details of complicated/RVVC had full yeast identification and antifungal susceptibility performed. Differences in prevalence between 12-month periods were determined using χ2 tests. Results Over the 3 years, cultures were performed on 5461 vaginal samples from women with clinical information indicating they had complicated/RVVC, RVVC, with 1828 (33.5%) growing yeasts. Over 85% of yeasts each year were C. albicans, however the proportion declined yearly with an increase in NCAY species. Nakaseomyces glabrata was the most frequent NCAY species isolated, increasing from 2.8% in 2018–19 to 6.8% in 2020–21. Total NCAY species increased from 6.0% in 2018–19 to 12.6% in 2020–21. Fluconazole-sensitive dose-dependant (SDD) and resistant isolates increased from 3.5% in 2018–19 to 7.7% in 2019–20 and 9.6% in 2020–21. Most resistance was in C. albicans and the majority of cases were seen in primary care. Most fluconazole non-sensitive isolates were either SDD or resistant to itraconazole (77% and 23%, respectively) and were intermediate or resistant to voriconazole (36.4% and 60%, respectively). Conclusion There was a significant increase in the prevalence of NCAY and fluconazole-resistant C. albicans in complicated/RVVC cultures over these 3 years. Successful treatment of such cases can be very challenging. The exact reasons for this increase remain unclear but it follows a policy change that encouraged a clinical diagnosis and empirical treatment of vulvovaginal candidiasis, rather than fungal culture, in primary care.