3种氨基糖苷类抗生素对大肠杆菌的联合抑制作用特点

Characteristics of Combined Inhibitory Effects of Three Aminoglycoside Antibiotics on Escherichia coli

抗生素的滥用,对人类及其生存环境均造成了影响。以3种氨基糖苷类抗生素:硫酸阿布拉霉素(apramycin sulfate,APR)、双氢链霉素(dihydrostreptomycin sulfate,DIH)和新霉素硫酸盐(neomycin sulphate,NEO)为研究对象,以大肠杆菌(Escherichia coli,E.coli)为受试生物,运用均匀设计射线法设计抗生素的三元混合物体系,共5条具有不同浓度配比的射线,应用时间毒性微板分析法系统测定抗生素及其三元混合物在5个不同暴露时间(0.25、2、4、8和12 h)的抑制效果,应用浓度加和模型分析毒性相互作用,并应用拟合归零法定量表征毒性相互作用强度,通过电镜扫描分析E.coli细胞的变化情况。结果表明:APR、DIH、NEO及其三元混合物对E.coli的抑制率均具有明显的时间依赖性,暴露时间不同,3种抗生素的半数浓度效应(EC 50)的负对数(pEC 50)值大小顺序不同,在12 h大小顺序为DIH>APR>NEO;5条混合物射线对E.coli在2~8 h时呈现出既有协同又有拮抗作用,随着暴露时间的延长,协同作用强度不断减小,在12 h转变为拮抗作用;随着浓度的增大,组分间的相互作用强度(dCA值)先增强后减小,其中射线R4在4 h时,浓度为2.74E-06 mol·L^(-1),混合物的dCA值达到最大值15.70%;3种抗生素及其三元混合物对E.coli作用主要是通过破坏其细胞形态和结构,使其出现内陷、坍塌和变形。

The abuse of antibiotics has caused serious harm to human beings and their living environment.So,three aminoglycoside antibiotics:apramycin sulfate(APR),dihydrostreptomycin sulfate(DIH),neomycin sulfate(NEO)were selected as research objects,and Escherichia coli(E.coli)as the test organism.The uniform design ray method was used to design the ternary mixture system of antibiotics.A total of 5 rays with different concentration ratios were arranged.The time-dependent microplate toxicity analysis method was used to determine the concentration-inhibition data of antibiotics and their ternary mixture at 5 different exposure time(0.25,2,4,8 and 12 h).Concentration addition(CA)model was used to analyze the toxicity interaction,and a return-to-zero fitting method was used to quantitatively characterize the strength of the toxicity interaction.The changes of E.coli cells were analyzed by scanning electron microscope.The results showed that the inhibition rates of APR,DIH,NEO and their ternary mixtures on E.coli were significantly time-dependent.Under different exposure time,the negative logarithm of median effect concentration(pEC 50)orders of the three antibiotics varied and the order was DIH>APR>NEO at 12 h.Five mixture rays showed both synergistic and antagonistic effects on E.coli at 2~8 h.The interaction intensity of the five mixture rays decreased with the extension of exposure time,and turned into antagonism at 12 h.With the increase of concentration,the interaction intensity between components first increased and then decreased.When the concentration was 2.74E-06 mol·L^(-1 )and the exposure time was 4 h,the dCA value of the mixture reaches the maximum value 15.70%.The effects of the three antibiotics and the ternary mixture on E.coli were mainly through the destruction of the cells’morphology and structure,causing them to invagination,collapse and deformation.