The Resistance Of Candida Albicans To Common Antifungal Drugs And Its Expression Of Cdr1 And Cdr2 Gene

Objective:To Investigate the Pathogenic Candida species and drug resistance in clinical Candida albicans strains, in order to make rational administration of antifungal agents and the expression of CDR1and CDR2 gene. To explore the relationship between CDR1 and CDR2 expression and Azole-resistance in clinical Candida albicans strains, so as to explore the mechanism of drug-resistance in Candida albicans.Methods:354 patients with vulvar pruritus or abnomal fluor albus were selected randomly from gynecologic clinic and they were checked with the same doctor. There 272 (76.84%)vulvovaginal candidiasis were cultivated and confirmed and Candida albicans was 217 (79.78%). According to the difference of the yeast fungus, Pathogenic Candida species were separate into two sets to identificate and analysis antifungal sensitivity in the Candida species, and did the same tests according to initial or recurrence. The target genes of drug resistance strains and the same number of sensitive ones as controls were amplified by RT-PCR with 2 couples of primer (CDR1/CDR2). Electrophoresis were used to check all PCR products for contrast analysis of Candida albicans CDR1 and CDR2 genesResults:From 272 strains of candida, candida albicans, C. glabrata, C. tropicalis,C. krusei were 79.8%(217/272),9.56%(22/272),8.1%(26/272),2.57%(7/272), respectively. The resistant rates of 272 Candida against amphotericin B, ketoconazole,miconazole,itraconazole,fluconazol,5-flucytosine,terbinafine and clotrimazole were 2.21%,0.74%,11.40%,27.57%,11.40%,7.35%,93.38%,16.54%,respectively. The resistant rates of 217 Candida albicans against amphotericin B, ketoconazole, miconazole, itraconazole, fluconazol,5-flucytosine,terbinafine and clotrimazole were 1.84%,0,5.99%,15.21%,6.91%,8.76%,94.93%,3.69%,respectively. The resistant rates of 55 non Candida albicans against amphotericin B, ketoconazole,miconazole,itraconazole,fluconazol,5-flucytosine,terbinafine and clotrimazole were 3.64%,3.64%,32.73%,76.36%,29.09%,1.82%,82.27%,67.27%, respectively. The antifungal sensitivity and pathogenic Candida species was no difference in patients with or without a history of VVC.No high number of resistant strains was observed for azole antifungals. The drug resistance genes CDR1 and CDR2 were over expressed in Candida albicans resistant strains. The incidences of CDR1 and CDR2 over expression in Azole-resistant strains were significantly higher than those in the Azole-sensitive stains with RT-PCR in candida albicans.Conclusion:The most common species in the clinical isolates were still Candida albicans,with non Candida albicans species appears increasing. The drug resistance of Candida to commonly used antifungals shows an ascending trend. Except terbinafine, Candida albicans strains were resistant to Azoles at different degrees, the non-Candida albicans resistence rates to Azole drugs were higher than Candida albicans. The antifungal sensitivity and pathogenic Candida species was no difference in patients with or without a history of VVC.No high number of resistant strains was observed for azole antifungals. Azole-resistance in clinical Candida albicans strains is related to the over expression of CDR1 and CDR2. Over expression of CDR1 and CDR2 can increase the efflux of drugs and therefore lead to drug-resistance. Other mechanisms may also participate in the development of drug resistance in the clinical Candida albicans strains.