夫西地酸对肺炎支原体及耐药肺炎支原体的体外抗菌作用

The antibacterial effect of Fusidic acid on Mycoplasma pneumoniae and antibiotic resistant Mycoplasma pneumoniae in vitro

目的探讨夫西地酸对肺炎支原体及耐药肺炎支原体的体外抗菌作用。方法选择28株2016年1月至12月就诊于首都医科大学附属北京友谊医院呼吸道感染患者的肺炎支原体临床分离株、2株肺炎支原体标准株进行研究。采用微量倍比稀释法测定夫西地酸、阿奇霉素对肺炎支原体的体外最低抑菌浓度（MIC）；棋盘法测定夫西地酸与阿奇霉素联用对肺炎支原体及耐药肺炎支原体的抗菌效果；通过测定夫西地酸在不同质量浓度下的抑菌速度评价夫西地酸的抑菌活性。结果28株临床分离株中，1株无耐药相关位点突变，1株含23SrRNA 2064位点突变，26株含23SrRNA 2063位点突变。微量倍比稀释法结果显示，阿奇霉素对含耐药相关位点突变的肺炎支原体临床株的MIC值〉1.000 0 mg/L，阿奇霉素对无耐药相关位点突变的肺炎支原体临床株的MIC值〈0.500 0 mg/L；夫西地酸对肺炎支原体及耐药肺炎支原体的MIC值均为1.000 0 mg/L。夫西地酸与阿奇霉素联用对肺炎支原体的分级抑菌浓度指数≤0.500 0，具有协同作用。在药物质量浓度≤32 MIC时，药物质量浓度越高，夫西地酸对肺炎支原体的抑菌效果越明显；药物质量浓度≤8 MIC时，菌株暴露于药物的时间越长，夫西地酸对肺炎支原体的抑菌效果越强。结论肺炎支原体感染治疗效果不佳或合并细菌感染时，应用或联合应用夫西地酸，可能抑制病原菌，临床治疗过程中如何应用需要进一步探讨。

ObjectiveTo investigate the antibacterial effect of Fusidic acid on Mycoplasma pneumoniae and antibiotic resistant Mycoplasma pneumoniae in vitro.MethodsTwenty- eight clinical strains of Mycoplasma pneumoniae isolated from patients with respiratory tract infection at Beijing Friendship Hospital Affiliated to the Capital University of Medical Sciences from January to December 2016 and 2 Mycoplasma pneumoniae reference strains were enrolled.The minimum inhibitory concentration （MIC） of Fusidic acid and Azithromycin were determined by using micro-dilution ration method.The chessboard method was used to check the antibacterial effect of combination between Fusidic acid and Azithromycin.The antibacterial activity of the Fusidic acid was evaluated by measuring the antibacte-rial rate of different concentrations.ResultsOne isolate showed no mutation in 23SrRNA, 26 isolates had one point mutation in loci 2063 and 1 isolate had one point mutation in loci 2064 among the 28 clinical isolates.The findings by micro-dilution method results showed that the MIC values of all the clinical isolates with mutations associated with macrolide resistance to Azithromycin were 〉1.000 0 mg/L, and the MIC values of all the clinical isolates with no mutations to azithromycin were 〈0.500 0 mg/L.The findings by micro-dilution method results showed that the MIC value of Fusidic acid for Mycoplasma pneumonia and drug resistance Mycoplasma pneumoniae was 1.000 0 mg/L.The Fractional Inhibitory Concentration index of Fusidic acid and Azithromycin combination was ≤0.500 0 mg/L.When the concentration of the Fusidic acid was lower than or equal to 32 MIC, the antibacterial effect of Fusidic acid against Mycoplasma pneumoniae increased with its higher concentration.When the concentration of the Fusidic acid was lower than or equal to 8 MIC, the longer the strain was exposed to the drug, the stronger antibacterial effect was against Mycoplasma pneumoniae.ConclusionIf the treatment of Mycoplasma pneumoniae infection is not effective or the infection of patient is combined with bacteria, the application or combination of Fusidic acid may inhibit pathogenic bacteria effectively.Of course, how to use Fusidic acid in clinical treatment needs further study and discussion.