Lack of in vitro resistance of Candida albicans to ketoconazole, itraconazole and clotrimazole in women treated for recurrent vaginal candidiasis.

OBJECTIVE To determine whether in vitro resistance of Candida albicans to the imidazoles (ketoconazole, clotrimazole and itraconazole) is associated with recurrence of candida vaginitis. DESIGN Candida isolates were collected before, during and after treatment from women with recurrent vaginal candidiasis (> or = 4 episodes/year), randomised into two prospective studies: (1) 56 women treated with ketoconazole 400 mg/daily for 7 days; (2) 44 women randomised to receive itraconazole 200 mg orally, or clotrimazole 200 mg intravaginally, twice weekly for six months. SETTING Women's Candida Clinic at St. Michael's Hospital, a University of Toronto teaching Hospital, Toronto, Ontario, Canada. MAIN OUTCOME, MEASURES: Isolates of yeasts recovered pre and post treatment were tested for significant changes in 50% inhibitory concentration (IC50). Resistance was defined as a greater than fourfold increase in baseline IC50 of post treatment isolates compared with pretreatment isolates. RESULTS Over 250 strains of C albicans were tested and none showed development of resistance to any of the agents. CONCLUSION Recurrence of vaginal candidiasis is not related to the development of drug resistance.