The effect of azidothymidine on germ tube formation in Candida albicans

Candida albicans have a marked propensity to cause infections in AIDS patie nts. A virulent trait of C. albicans is the yeast-hypha transition (Y-->H) which is influenced, in vitro and in vivo, by several factors. Since azidot hymidine (AZT) is used in HIV-positive patients, the effect, in vitro, of d ifferent concentrations of AZT on C. albicans Y-->H transition was evaluate d. C. albicans isolated from HIV-negative and HIV-positive patients were us ed and strains of C. tropicalis isolated from HIV-positive patients were al so tested. AZT concentrations from 0.01 mu g/ml to 10 mu g/ml did not have any influence on the Y-->H transition, whereas 100 mu g/ml AZT significantl y inhibited the germ tube formation. AZT did not influence the formation of pseudohyphae in C. tropicalis. It is suggested that C. albicans infection observed in HIV-positive patients was not influenced by AZT therapy, becaus e at currently used dosages, the Y-->H transition was not expected to incre ase.