The Impacts Of Genotype, PH And Dimorphism On Adherence And Atifungal Susceptibility Of Vaginal Candida Albicans

Objective1. To explore the impacts of genotype, pH and dimorphism on adherence of vaginal Candida albicans to Vaginal epithelial cell (VEC) in vitro.2. To investigate the impacts of genotype, pH and dimorphism on antifungal susceptibility of vaginal Candida albicans.MethodAll the Candida albicans isolates were cultured from samples obtained from patients with VVC of the Gynecology outpatient.1. Polymerase Chain Reaction (PCR) was used to amplify the intron area of the 25S rDNA of Candida albicans. The adherence rate of yeast and mecylium of different genotype Candida albicans to VEC at pH7.0 and pH4.0 were calculated.2. The antifungal susceptibility of different genotype Candida albicans in two-form under pH7.0 and 4.0 to 6 agents were detected by the broth microdilution methods proposed by the National Committee for Clinical Laboratory Standards (NCCLS).Results1. A total of 954 strains of Candida albicans were divided into three types:876 (91.8%) genotype A strains,58 (6.1%) genotype B strains and 20 (2.1%) genotype C strains.The adherence rates of the yeast form of different genotypes were A>B>C (P< 0.001). The rates of the mecylial form were higher than those of the yeast form, and those at pH4.0 were significant higher than those at pH7.0 (P<0.001).2. The susceptibility of agents were determined according to the NCCLS breakpoints.(1) the MICs of itraconazole against genotype C was significantly lower than those of genotype A and B, and those of fluconazole against genotype A was significantly higher than those of genotype B and C (P<0.05). The susceptibility rate of the 3 types to the five agents shown no significant difference (P>0.05).(2) The MICs of itraconazole against Candida albicans at pH4.0 was lower than that at pH7.0, while The MICs of miconazole, clotrimazole, fluconazole,nystatin and terbinafine at pH4.0 were significantly higher than those at pH7.0 (P<0.001). The susceptibility rate of the Canidia albicans to itraconazole at pH4.0 (95%) was significantly higher than that at pH7.0 (51.7%). while nystatin was in an opposite situation (0%,98.3%).(3) The MIC values of miconazole and itraconazole against Candida albicans in mycelial form were significantly higher than those in yeast form, while the nystatin was in an opposite situation (P<0.01). The susceptibility rate of the Candida albicans in mycelial form to itraconazole (98.3%) was significantly higher than that in yeast form (51.7%). while the nystatin was in an opposite situation (P<0.01).(4) Compared with the values of the routine drug susceptibility test (pH7.0, the yeast- form), the MICs of the individual susceptibility test (pH4.0, the mycelial-form) of itraconazole were lower, while the other five agents were in an opposite situation (P<0.01). The sensitivity of Itraconazole of the latter was higher than those of the former, Nystatin and Terbinafine is the opposite. The susceptibility rate of the Candida albicans in the individual test to itraconazole (86.7%) was significantly higher than that in the routine test (51.7%). while the nystatin was in an opposite situation (P<0.01).Conclusion1. The main genotype of the Candida albicans isolated from the vaginal discharge of patients with VVC is A. These results suggest that the genotype, environment pH and dimorphism affected the adhesion capability of vaginal Candida albicans to VEC.2. The genotype, dimorphism and pH affect the antifungal susceptibility of vaginal Candida albicans. Azoles remain the first choice. Maybe doing the the sensitivity test according to the real growth environment and the characteristic of Candida albicans is reasonable.