三种喹诺酮类药物的体外抗菌活性和防突变能力评价OA

AIM:To evaluate the in vitro antibac-terial efficacy of three quinolones—nemonoxacin,levofloxacin,and moxifloxacin—against Gram-posi-tive(G+)and Gram-negative(G-)bacteria,providing a scientific basis for rational clinical use.METHODS:Drug susceptibility tests were conducted on 292 clinical isolates(including Staphylococcus aureus,Staphylococcus epidermidis,Enterococcus faecium,Corynebacterium striatum,Escherichia coli,Klebsiel-la pneumoniae,Pseudomonas aeruginosa,and Acinetobacter baumannii)using the broth microdi-lution method to compare the distribution of mini-mum inhibitory concentrations(MICs)and pharma-codynamic characteristics.The mutant prevention concentration(MPC)of selected strains was further determined by the agar dilution method to evalu-ate their mutant prevention capabilities.RESULTS:For G+bacteria,nemonoxacin exhibited superior ac-tivity against Staphylococcus aureus(MIC90=16 μg/mL),Staphylococcus epidermidis(MIC90=2 μg/mL),and Corynebacterium striatum(MIC90=4 μg/mL)compared to levofloxacin and moxifloxacin.In MRSA strains,the susceptibility rate of nemonoxacin reached 66.96%.For G-bacteria,the MIC90 of levofloxacin against P.aeruginosa was 2 μg/mL,which was lower than that of nemonoxacin and moxifloxacin(both 4 μg/mL).For K.pneumoni-ae,E.coli,and A.baumannii,the MIC90 values for all three drugs were mostly 64 μg/mL,indicating over-all low susceptibility.In terms of mutant preven-tion,nemonoxacin showed an MPC90 of 2 μg/mL in MSSA,which was lower than that of moxifloxacin(4 μg/mL)and levofloxacin(16 μg/mL),with the nar-rowest range of selection index(SI).In resistant G—bacteria,the MPC90 and SI values for all three drugs were generally higher.However,the MPC90 of lev-ofloxacin against resistant P.aeruginosa(16 μg/mL)was lower than that of moxifloxacin(32 μg/mL)and nemonoxacin(64 μg/mL).CONCLUSION:Nemonoxacin demonstrates stronger antibacterial activity against G+bacteria such as S.aureus(includ-ing MRSA)and possesses the most potent mutant prevention capability in MSSA.Levofloxacin main-tains favorable antibacterial activity against P.aeruginosa,and its MPC is relatively lower among the tested drugs.Clinical selection should be based on the specific pathogen type and the risk of resis-tance.