Study On In Vitro Antifungal Activity Of Itraconazole Combined With Saps Enzyme Inhibitor Ritonavir In Candida Albicans

Objective:1.To investigate the difference of different media(RPMI 1640 medium and YCB-BSA medium)in drug susceptibility of C.albicans in vitro..2.To investigate the effect of ITR combined with Saps enzyme inhibitor RIT on the antifungal activity of C.albicans in vitro.Methods:1.Thirty-two clinical strains of suspected C.albicans were collected from the drug sensitivity laboratory of the Second Hospital of Shanxi Medical University from February to March 2021,and were further identified by using Candida chromogenic medium and molecular biological methods.The identified strains were tested by the Clinical and Laboratory Standards Institute recommended M27-A4 microbroth dilution method and Yeast carbon base and bovine serum albumin were used to conduct ITR drug sensitivity test in vitro,and their MIC50 values were read and recorded.If the numerical variables fit the normal distribution,they will be expressed as the mean ± standard deviation((?)±S);otherwise,they will be analyzed by the nonparametric test.In order to P<0.05 was considered statistically significant.2.Twenty-seven strains identified as C.albicans from the first part were selected.Using YCB-BSA as the growth medium,RIT combined with ITR in vitro drug sensitivity test was carried out using the chessboard method.The experimental results were interpreted by MIC50 value according to CLSI M27-A4.In the first part,the MIC of ITR single drug was recorded as ITR-MIC1,and the MIC after combining with RIT(i.e.,when the minimum MIC measured by RIT single drug was the working concentration,the MIC50 value of ITR)was recorded as ITR-MIC2.The two were statistically analyzed.The differences of MIC50 values before and after treatment with YCB-BSA as medium were compared.If the numerical variables were in normal distribution,the mean ± standard deviation((?)±S)was used for analysis;otherwise,the non-parametric test was used for analysis,and the P > 0.05 was considered statistically significant.The formula ITR-MIC1/ITR-MIC2 was used to calculate the synergistic multiple after the combination of ITR and RIT to explore the effect of ITR combined with SAPS enzyme inhibitor ritonavir on the antifungal activity of C.albicans in vitro.Results:1.Through colorimetic culture and molecular biological identification of Candida,27 of the 32 suspected clinical strains were C.albicans.Among them,52%(14 isolates)were sensitive,7%(2 isolates)were dose-dependent,and 41%(11 isolates)were drug-resistant.2.Statistical analysis results of MIC50 values obtained from different media:The numerical variables did not fit the normal distribution and were expressed as the median± quad interval(M±Q).The values of RPMI 1640 group and YCB-BSA group were0.1250±15.9375 and 0.0625±0.0937,Z value was-2.196,P < 0.05,and the difference was statistically significant.In the drug-resistant group,the value of RPMI 1640 group was 16.0000±8.0000,and that of YCB-BSA group was 0.0625±0.0625,Z value was-4.098,P < 0.05,and the difference was statistically significant.In the sensitive groups,the values were 0.0625±0.0312 in RPMI 1640 group and 0.0625±0.0468 in YCB-BSA group,Z value was 1.085,P > 0.05,and the difference was not statistically significant.In the dose-dependent sensitive group,M±Q was not calculated in the RPMI 1640 group and the YCB-BSA group,and the calculated Z value was-1.549,P > 0.05,and the difference was not statistically significant.3.In the drug sensitivity test using YCB-BSA as growth medium,the MIC50 value of ITR single drug and the MIC50 value of ITR combined with RIT were statistically analyzed:The ITR single drug group was 0.0625±0.0937,the combination drug group was 0.0313±0.0000,Z value was-4.750,P value,< 0.05,the difference was statistically significant.4.The combined treatment of RIT and ITR could reduce the MIC50 value of ITR,and the MIC value of 74%(20/27)strains was reduced by 2 to 8 times.Conclusion:1.Some clinical strains collected in this study were resistant to ITR,accounting for41%.2.When replacing YCB-BSA medium for C.albicans drug susceptibility test in vitro,the MIC50 value obtained was different from that obtained by RPMI 1640 medium.3.Combined administration of RIT and ITR can reduce the MIC value of the latter,and to a certain extent,it can produce synergistic effect on ITR.