Changing virulence factors among vaginal non-albicans Candida species

Vulvovaginal candidiasis (VVC) is caused by overgrowth of Candida species in the female lower genital tract and most commonly caused by Candida albicans. The production of various virulence factors may attribute to their pathogenicity. Hence, this study was aimed to determine the production of various virulence factors of Candida spp. causing VVC.

A total of 51 Candida spp. were isolated prospectively from 50 patients among 211 clinically suspected cases of VVC. The haemolytic activity, biofilm production, proteinase activity, phospholipase activity and esterase activity were detected by standard methods. Statistical analysis was performed using OpenEpi version 3.01.

Haemolytic activity was observed in 42 Candida isolates (82.4%), biofilm activity in 21 Candida isolates (41.2%), proteinase and esterase activity in 19 Candida isolates (37.3%) each and phospholipase activity in 15 Candida isolates (29.4%). Phospholipase activity was observed in all of the C. albicans strains, whereas all strains of Candida krusei were able to produce biofilm. All strains of Candida parapsilosis and 87% strains of Candida glabrata were haemolytic. Five of the eight C. glabrata strains were found to produce strong proteinase (Pr_z score ≤0.63). About 30.4% strains of C. glabrata and 20% strains of C. krusei were found to be positive for esterase activity. This is one of the few studies which revealed esterase activity among C. glabrata and C. krusei strains.

This study highlighted that there is a change in the virulence factors among the non-albicans Candida species, especially C. glabrata strains which were haemolytic and produce strong proteinase activity and esterase activity. It may be one of the explanation of the most common causative agent of VVC in our study. Multicentric studies from this area might be required to get a more generalised conclusion.