Vulvovaginal candidiasis: histologic lesions are primarily polymicrobial and invasive and do not contain biofilms

The recent demonstration of a vaginal biofilm in bacterial vaginosis and its postulated importance in the pathogenesis of recurrent bacterial vaginosis, including relative resistance to therapy, has led to the hypothesis that biofilms are crucial for the development of vulvovaginal candidiasis. The histopathology and microbial architecture of vulvovaginal candidiasis have not been previously defined; neither has Candida, containing biofilm been reported in situ. The present study aimed at clarifying the histopathology of vulvovaginal candidiasis including the presence or absence of vaginal biofilm.

In a cross-sectional study, vaginal tissue biopsies were obtained from 35 women with clinically, microscopically, and culture-proven vulvovaginal candidiasis and compared with specimens obtained from 25 healthy women and 30 women with active bacterial vaginosis. Vaginal Candida infection was visualized using fluorescent in situ hybridization with ribosomal gene-based probes.

Candida microorganisms were confirmed in 26 of 35 biopsies obtained from women with vulvovaginal candidiasis; however, Candida containing biofilm were not detected in any of the cases. Histopathological lesions were exclusively invasive and accompanied by co-invasion with Gardnerella or Lactobacillus species organisms.

Histopathological lesions of vulvovaginal candidiasis are primarily invasive in nature and polymicrobial and do not resemble biofilms. The clinical significance of Candida tissue invasion is unknown.