Fluconazole-Resistant and Virulence-Associated Yeasts from the Vulva: Evidence of a Potential Reservoir

Vulvovaginal candidosis is an affliction caused by yeasts. Symptoms in the vulva are generally associated with the spreading of infected vaginal fluid. To better understand the role of the vulva in these dynamics, in this study we aim to fully identify and characterize non-Candida albicans vulvar yeast isolates. Fifty-four vulvar swabs were obtained from 31 women attending a gynecological consultation. After species identification, fluconazole susceptibility was assessed by the microdilution broth method. Biofilm biomass was quantified using crystal violet staining, and phospholipase and hemolysin production were assessed by plating a calibrated suspension in suitable culture media. Finally, adherence to cervical cells was assessed by infecting a monolayer of HeLa cells. Among the 54 vulvar isolates obtained, 12 different species were identified. About 54% (29/54) of vulvar isolates were resistant to fluconazole. All isolates were able to produce a high amount of biofilm biomass. Pichia kudriavzevii and Rhodotorula mucilaginosa were the only species that produced phospholipase; hemolysin production was detected in isolates belonging to almost all species. Almost all species had the ability to adhere to HeLa cells. These results indicate that the vulva act as a reservoir for fluconazole-resistant yeasts, which are also potentially virulent.