Virulence of Candida spp. Isolates From Patients With Recurrent Vulvovaginal Candidosis Is Associated With the Number of Episodes

Background: Recurrent vulvovaginal candidosis (RVVC) has been associated with increased antifungal resistance. Recently, we reported that Candida isolates from Colombian patients with RVVC did not show an increase in antifungal resistance. Objective: The aim of this study was to evaluate the virulence of Candida isolates from patients with RVVC. Methods: A total of 40 Candida isolates were evaluated (37 C. albicans and 3 C. lusitaniae). C. albicans isolates were divided into two groups based on the number of VVC episodes in patients per year: Group 1 (four to seven episodes; n = 26) and Group 2 (≥ eight episodes; n = 11). The XTT assay was used to assess biofilm formation. Galleria mellonella larvae were used for survival analysis and fungal load assessment, and the qPCR technique to determine the expression of the PRA1 gene. Results: It was observed that C. lusitaniae and C. albicans isolates from patients with ≥ eight VVC episodes per year exhibited a greater capacity to form biofilms compared to those from patients with four to seven VVC episodes. Moreover, in the G. mellonella model, larvae inoculated with isolates from RVVC patients exhibited approximately 80% mortality. Similarly, larvae infected with C. albicans from patients who experienced ≥ eight VVC episodes showed a significantly higher fungal load compared to the other evaluated groups; likewise, the expression of the PRA1 gene was significantly higher in isolates from patients with ≥ eight VVC episodes. Conclusion: These results indicate that Candida isolates from patients with RVVC exhibit a high degree of virulence and suggest that virulence may be one of the mechanisms explaining recurrence rather than antifungal resistance itself.