A Simplified Technique for Evaluating the Adherence of Yeasts to Human Vaginal Epithelial Cells

Thousands of women all over the world annually suffer of vulvovaginal candidiasis (VVC), an infection caused by yeasts, which mainly affect the mucosa of the vulva and vagina. The adherence of the yeasts to the mucosae is an essential step for colonization and predisposes the start of the infectious process. In this study, a technique capable of evaluating the adhesion of yeasts to human vaginal epithelial cells (HVEC) was employed. Twenty-five vaginal yeast isolates (10 Candida albicans, nine C. glabrata, two C. parapsilosis, one C. tropicalis, two Saccharomyces cerevisiae, and one Trichosporon sp.) were evaluated. A suspension of each yeast was co-incubated with HVEC obtained from a healthy donor in the ovulatory phase. After 1 hr, smears were made, stained with crystal violet and Papanicolaou, and the number of yeasts that adhered to 600 HVEC was evaluated. The adhesion of C. albicans was significantly greater than that of the other species and occurred mainly in the intermediate HVEC, rather than the superficial. In addition, the proposed technique, easy to execute and of low cost showed to be reproducible and enables the determination of the adherence capacity of different isolates, whose adhesion was confirmed by scanning electron microscopy.