Isolation, acid proteinase secretion, and experimental pathogenicity of Candida parapsilosis from outpatients with vaginitis.

Candida parapsilosis was isolated from the vaginas of several nonpregnant, nondiabetic, mostly premenopausal outpatients who presented the characteristic signs and symptoms of a frank vulvovaginal candidiasis (heavy discharge with cottage cheese appearance and intense itching, with or without vulvar erythema and dyspareunia). All isolates conformed morphologically, biochemically, and serologically to the standard description of the species. They showed high acid proteinase-secretory activity in vitro and were appreciably pathogenic for cyclophosphamide-immunodepressed mice. Some isolates were also tested for their vaginopathic potential in ovariectomized rats under estradiol administration. In all cases, the rat vagina was colonized by C. parapsilosis to an extent and duration not different from those caused by a vaginopathic isolate of Candida albicans. Periodic acid-Schiff-stained vaginal smears taken at intervals during rat experimental infection showed C. parapsilosis yeasts adhering to exfoliated epithelial cells of rat vagina. Overall, these results emphasize the proteolytic and pathogenic potential of C. parapsilosis and suggest that this fungus may be an agent of clinical vaginitis.