五味子对禽源大肠杆菌临床分离株抗生素敏感性的影响

The effects of fructus Schisandrae chinensis on the sensitivity of antibiotics against clinical isolated drug-resistant Escherichia coli

研究五味子水煎液的体外抗菌活性及与临床常用6种抗生素联合对临床分离6株耐药大肠杆菌(E.coli)的作用效果。采用微量肉汤稀释法测定南五味子水煎液(SRD)、北五味子水煎液(SCD)以及6种抗生素对临床分离禽源E.coli的最低抑菌浓度(MICs);微量棋盘法测定SCD与6种抗生素联合对E.coli的分级抑菌浓度指数(FICI);平板计数法测定SCD以及SCD与CEF联合对E.coli ATCC25922生长的影响。结果显示:SCD对6株耐药菌的MIC均为64 mg·mL^(-1),SRD对其中5株的MIC为128 mg·mL^(-1),对另一株的MIC>128 mg·mL^(-1);SCD与头孢噻呋(CEF)联用时对5株菌的FIC≤0.5,呈协同作用;与恩诺沙星(ENR)联用时对6株菌的FIC>2,呈拮抗作用;与卡那霉素(KAN)、链霉素(STR)、氨苄西林(AMP)和多西环素(DOX)联合时主要呈相加作用;SCD能抑制E.coli生长速度,使其生长量明显降低,且相较于单独处理,1/4MIC SCD与1/4MIC CEF联合处理的抑菌效果更明显。综上,SCD的抗菌活性强于SRD,且能明显增强禽源临床分离耐药E.coli对CEF的敏感性而呈现协同抑菌作用。

In this study,we investigated the antimicrobial activity of Schisandra chinensis Baill decoction(SCD)and Schisandra sphenanthera Rehd.et Wils decoction(SRD)and the effects while combined with six antibiotics against 6 clinical E.coli isolates.The minimum inhibitory concentrations(MICs)of SRD,SCD alone and in combination with 6 antibiotics against avian pathogenic E.coli was determined by micro-broth dilution method.The fractional inhibitory concentration index(FICI)of SCD combining with 6 antibiotics against E.coli was determined by micro-checkerboard dilution method.The growth curve of E.coli ATCC25922 effected by SCD and combinaion with ceftionfur(CEF)were analyzed by counting method.The results showed that MICs of SCD were 64 mg·mL^(-1) against 6 strains,the MICs of SRD were equal or more than 128 mg·mL^(-1).The combination of SCD and ceftiofur(CEF)showed synergy against 5 of all 6 strains with the FICI not more than 0.5;the combination of SCD with enrofloxacin(ENR)showed an antagonistic effect against all tested strains with the FICI more than 2;the combination of SCD with kanamycin(KAN),streptomycin(STR),ampicillin(AMP),or doxycycline(DOX)mainly showed additive effect.SCD decelerated bacterial growth and reduced its dosage;the antibacterial effect was more potent than single treatment when 1/4 MIC SCD combined with 1/4 MIC CEF.In conclusion,the antibacterial activity of SCD is more potent than that of SRD,it can significantly enhance the sensitivity of clinical drug-resistant E.coli isolates to CEF with a synergistic action.