Comparative in vitro activity of antimycotic agents against pathogenic vaginal yeast isolates

Although numerous antimycotic agents are available for the treatment of yeast vaginitis there is little comparative data on the in vitro activity of these drugs. In the present two-part study, in vitro macro-broth dilution sensitivity tests were performed on a total of 377 clinical vaginal yeast isolates of nine different species. Antimycotics surveyed included amphotericin B, 5-fluorocytosine and eight azole derivatives. Results show that all vaginal Candida albicans isolates were uniformly sensitive at low concentration to all 10 antimycotics tested. However, non-albicans species, especially Candida glabrata and Saccharomyces cerevisiae, manifested several-fold increases in minimal inhibitory concentrations to all azoles tested except butoconazole. In particular, the in vitro potency of fluconazole and terconazole against species other than C. albicans was relatively poor, whereas the drugs demonstrating the best activity were itraconazole, butoconazole and saperconazole. Susceptibility testing of vaginal C. albicans isolates is not routinely indicated, even in patients with recurrent vaginitis and should be reserved for selected organisms, especially non-albicans species, in patients with clinical failure only.