A Study On Mechanisms Of Antifungal Resisitance Of Candida Albicans Isolated From RVVC

Objective:①o determine the susceptibilities of Candida albicans(C.albicans) isolated from RVVC (Recurrent Vulvovaginal candidiasis) to seven kinds of antifungal drugs in vitro.②To identify expression of the ATP binding cassette transporters—CDR1, CDR2, PDR1and the multi-drug resistance MDR1, and to confirm the role of efflux pumps genes in antifungal resisitance of C.albicans isolates from RVVC.Methods:①A total of243Candida isolates, including84isolates from RVVC patients and159isolates from VVC patients, were identified with chromogenic medium CHROMagar (CHROMagar Co.France), the chromogenic medium of Autobio and the VITEK2(bioMerieux);②Antifungal susceptibility test in vitro was preformed by BIOKONT fungus kits(FUNGUS-7), which including two kinds of Polyene antifungul drugs,four kinds of azoles and5-fluoroctosine.;③All Candida isolates were divided into three groups (susceptible, susceptible dose dependent and resistant) according to antifungal susceptibility. Amplicated with realtime fluores-cence quantitative PCR (RTFQ PCR),the expressions of CDR1, CDR2, PDR1and MDR1were compared among different groups.Results:①The proportion of C.albicans from RVVC is90.48%while the other9.52%belongs to non-C.albicans; C.albicans from VVC is identified up to88.68%while the rest are non-albicans. The statistic difference between the proportion of C.albicans in RVVC and VVC is not significant (P>0.05);②The isolates from RVVC showed the antifungal susceptibility order as nystatin>amphotericin B>5-fluorocytosine>econazole>miconazole>fluconazole>itraconazole, while those from VVC showed the antifungal susceptibility order as amphotericin B>nystatin>5-fluorocytosine> miconazole> econazole> fluconazole> itraconazole. The isolates from RWC were more susceptible to nystatin and miconazole than those from WC(P<0.05);③The expression of PDR1could be found in part of isolates. The percentage of PDR1expressed isolates from RVVC was significantly lower than that of VVC(P<0.05).For5-fluorocytosine, The quantity of PDR] expression in VVC-R was significantly higher than that of WC-S and VVC-I(P<0.05).In the case of itraconazole, the quantity of PDR1expression in RVVC-R was higher than that in WC-S, WC-R and RVVC-S groups(P<0.05). The expression of CDR1. CDR2, MDR1could be seen in all isolates, but only the expression quantity of CDR1showed significant difference. In the case of miconazole, the expression quantity in VVC-I+R was higher than WC-S(P<0.05).In the case of fluconazole, the expression quantity of CDR1in WC-I group was the highest, comparing with in WC-S and VVC-R groups(P<0.05). In the case of amphotericin B, the quantitity of CDR1expression in VVC-R was higher than that in VVC-S and VVC-R groups(P<0.05).Conclusions:①albicans is dominant isolate of RWC.of RWC.②he chromogenic medium is applicable for clinically fast identification of C.albicans whereas the identification of non-C.albicans is limited.③The antifungal susceptibilities of C.albicans from RVVC’and WC are similar, and nystatin is the best choice.④PDR1and CDR1are related to antifungal drug resistance.⑤esides expression of antifungal drug resistance genes, the other factors may play important role in antifungal drug resistance.