Recurrent vulvovaginal Candida spp isolates phenotypically express less virulence traits

Vulvovaginal candidosis (VVC) is a condition that impacts the quality of life of women worldwide. At least 5-8% of all VVC cases re-occur. Recurrent vulvovaginal candidosis (RVVC) can be defined as the occurrence of a VVC episode at least four times per year. The reasons for recurrence to occur are poorly understood. This work aims to identify key phenotypic traits associated with RVVC Candida spp. isolates that might be used to plan strategies to control RVVC.

The capacity to form biofilms (with the microtitration plate assay), to develop germinative tube in the presence of fetal bovine serum and to produce phospholipase (in the egg-yolk plate assay) was assessed for a collection of Candida spp. isolates obtained from 17 women diagnosed with RVVC and 16 women with non-recurrent VVC (VVC). The differences obtained regarding the proportion of isolates expressing each virulence factor was assessed by statistical analysis (χ²).

We found that C. albicans isolates had a higher ability to form germinative tubes than RVVC isolates (29% vs 4%, p < 0.05). In addition, the ability of Candida spp. isolates to form biofilm (63% vs 51%) and to produce phospholipase (13% vs 11%) was also higher, though not statistically different (p > 0.05).

We conclude that biofilm formation and phenotypic-switching associated with germinative tube production are particularly important C. albicans virulence factors for acute, sporadic VVC cases.