Abstract: There are three described mechanisms of azole resistance:reduced membrane permeability,alteration in the target fungal enzyme,and over production of the target enzyme.We conducted a study on 26 strains of fluconazole (FCZ) resistant Candida albicans which were isolated from AIDS patients as well as 5 FCZ resistant colonies which were induced from ATCC 14053 by physical(UV) and chemical(diethyl sulfate) means.Firstly,6 sets of primers were selected from the gene encoding the target enzyme of Candida albicans,and the results of DNA amplification showed that several tested strains were negative for some primers,that is to say:there was no expected DNA band appeared.In order to know whether it lacks of the target enzyme coding gene(in this case,it will be resistant to fluconazole)or not,we used the target enzyme coding gene of Candida albicans ATCC 14053 as a probe to hybridize with the genome DNA of those negative strains,and the result was positive.This indicated that their target genes were existed and probably there was mutation at the site which corresponded to the primers,and especially the latter one.Certainly,this conclusion needs to be further proved.Then,we conducted the polymerase chain reaction single strand conformation polymorphism(PCR SSCP) analysis.There were differences between the resistant strains and the sensitive ones and inter resistant strains also.Therefore,we propose that multi mutation of the gene encoding the target enzyme is probably one of the resistant mechanisms.

Key words: Candida albicans, Fluconazole-resistant, Resistant mechanism