Effects Of Vancomycin Alone And Combined Use Of Drugs On The Drug Resistance Of MRSA

?Objective?:The Methicillin-resistant Staphylococcus aureus?MRSA?that were the clinical isolates were cultivated and detected by the First Affiliated Hospital of Bengbu Medical College in 2015.The Bacterial culture medium with vancomycin alone and in combination with rifampin and fosfomycin were cultured.The vancomycin anti-infective therapy and anti-infective therapy combined with other antimicrobial agents were compared.The effects of vancomycin alone and in combination with others on MRSA drug resistance were observed.?Methods?:The culture mediums were prepared by agar plate multiplier dilution method.The concentration were 10¹⁰ CFU·ml-1.The concentrations of anti-drug-resistant mutants in the above strains were tested.And the selection index and frequency of drug resistance were also calculated.?Results?:MPC of vancomycin combined with rifampicin and fosfomycin were?7.800±3.584?and?3.600±2.011?,respectively.MPC of vancomycin alone was?30.400±14.095?.MPC of in combination with rifampicin or fosfomycin were lower than MPC of vancomycin alone.And the difference was statistically significant?F=29.242,P<0.001?by ANOVA.The SI of vancomycin with rifampicin and fosfomycin were?8.600±4.427?and?3.800±1.932?,respectively.The SI of vancomycin alone was?32.000±13.064?.The SI of vancomycin combined with rifampicin and the SI of vancomycin combined with fosfomycin were superior to the SI of vancomycin alone through three SI comparison.The variance was statistically significant?F=35.202,P<0.001?by ANOVA.At the same time,the SI of vancomycin combined with fosfomycin was significantly lower than the SI of vancomycin combined rifampicin through two SI comparison.And the difference was statistically significant by LSD-t test?t=4.712,P=0.001?.The drug resistance frequency of 10 strains of MRSA were1.50*10-5-2.54*10-6,2.42*10-6-1.86*10-7,7.85*10-6-5.66*10-7,3.28*10-7-1.61*10-8,1.70*10-8-3.34*10-9,2.34*10-9,in turn,vancomycin alone1*MIC,2*MIC,4*MIC,8*MIC,16*MIC and 32*MIC.The frequency of Vancomycin combined with rifampicin was better than that of Vancomycin alone.And the difference was statistically significant?t=4.826,P=0.003?by t test.The frequency of Vancomycin combined with fosfomycin was also better than that of Vancomycin alone.The difference was statistically significant?t=4.901,P=0.004?through compared with t test.The drug resistance frequency of Vancomycin combined with fosfomycin and rifampin were better than that of vancomycin alone.?Conclusions?:The purpose of this study was to investigate the resistance effects of vancomycin alone and in combination with others on the 20 strains of MRSA.The antibacterial drug concentration at the lowest mutation rate was obtained from the experimental data.The results showed that there was significant difference between the data of vancomycin alone and in combination with fosfomycin and rifampicin.The difference between the two groups was significant?P<0.01?.The results showed that neither vancomycin combined with fosfomycin or combined with rifampicin can effectively reduce MPC,and the probability of drug resistance occurrence also decrease,and MSW also narrowed compared with vancomycin alone.