Vulvovaginal Candidiasis Caused by Candida krusei (Pichia kudriavzevii), Still a Formidable Challenge.

Objectives: In recent years, the prevalence of non-albicans Candida vulvovaginitis has risen with Candida glabrata and Candida krusei (Pichia kudriavzevii) being prominent contributors. Candida krusei poses a significant challenge due to its intrinsic resistance to fluconazole, both in vitro and clinically. Practitioners face difficulties managing patients with chronic symptomatic vulvovaginal candidiasis who fail to respond to multiple courses of oral fluconazole and over the counter (OTC) antifungals.

Methods: We analyzed retrospectively a cohort of women who had chronic vulvovaginal symptoms seen in our vaginitis clinic between 2017 and 2024. Clinical charts of 11 patients with positive C. krusei vaginal fungal isolates were reviewed. Antifungal susceptibility of isolates was assessed, and treatments, including novel antifungal agents oteseconazole and ibrexafungerp, were evaluated for their efficacy in symptom control.

Results: In 10 of 11 patients, symptoms were attributed to C. krusei vaginitis, while in 1 patient, C. krusei was found to be an innocent bystander. Candida krusei vaginal isolates in vitro susceptibility testing demonstrated resistance not only limited to fluconazole but also to miconazole, ketoconazole, and other azole agents. Although itraconazole exhibited in vitro activity, treatment often failed to achieve clinical or mycologic remission. Despite the availability of new antifungal agents, vaginal boric acid emerged as the initial if not definitive treatment method of choice.

Conclusion: Determining the antifungal susceptibility profile of C. krusei vaginal isolates may be required in selecting effective antifungal treatment of refractory vaginitis due to non-albicans Candida (NAC).