Background: Yeast vaginitis is a common infection. Data on the identity and prevalence of the etiological species would serve both epidemiological and therapeutic ends. Proteinase secretion by the invading yeast has been implicated in facilitating infection. Hence a prospective study was conducted to determine the species causing vaginitis in women from Saudi Arabia and the yeast’s ability to produce proteinase.
Material/Methods: The subjects were patients with clinical signs of vaginitis. A high vaginal swab specimen from each patient was cultured, and only women yielding heavy yeast growth were enrolled. The isolated yeasts were identified by routine procedures, then evaluated for proteinase production in a medium containing bovine serum albumin.
Results: A total of 500 patients were studied. Candida albicans was the major species to cause vaginitis (59%), followed by C. glabrata (31%), C. tropicalis (4%), C. krusei (3.2%), Saccharomyces cerevisiae (1.6%), C. parapsilosis (0.6%), and C. kefyr (0.6%). All isolates of C. albicans and C. parapsilosis and 95% of C. tropicalis produced proteinase, while isolates from the remaining species did not.
Conclusions: These results indicate that 59.6% of yeast vaginitis in women from Saudi Arabia is caused by C. albicans, and 31.6% by C. glabrata. Of relatively low prevalence were C. tropicalis and C. krusei. The study also revealed that both proteinase producers and non-producers were involved in causing vaginitis, indicating that proteinase secretion is not an essential factor in the pathogenesis of yeast vaginitis.

Keywords: Yeast vaginitis, Candida, secretory acid proteinase