不同有机酸联用对大肠杆菌的抑制作用

Inhibitory of different organic acid combinations against Escherichia coli

有机酸在抑制致病菌方面具有重要的应用价值。该文以大肠杆菌ATCC25922为指示菌,使用微量稀释法和棋盘格法确定多种有机酸及其组合的最小抑菌浓度,半数有效抑菌浓度和联合抑菌指数。并通过对大肠杆菌细胞膜电位和微观形态的观察,研究不同有机酸组合的联合抑菌效应。结果表明,乙酸、乳酸和丁酸的最小抑菌浓度为2560μg/mL,柠檬酸和苹果酸的最小抑菌浓度为5120μg/mL;乙酸、乳酸、丁酸、柠檬酸和苹果酸的半数有效抑菌浓度分别为1004.90、1497.50、964.32、1406.02、1727.72μg/mL。乙酸和乳酸联用表现为相加作用,乙酸、乳酸和第3种有机酸(丁酸、柠檬酸、苹果酸)联用表现为协同作用;有机酸及其组合会导致大肠杆菌膜电位下降,多数菌体出现收缩、弯曲变形。

Organic acids are known to have important applications in pathogenic bacteria inhibition.The microdilution and checkerboard grid methods were used to determine the minimum inhibition concentration,median effective concentration,and fractional inhibitory concentration index of organic acids inhibited E.coli ATCC25922.The combined antibacterial effect of the organic acid combinations was investigated by observing the cell membrane potential and micromorphology of E.coli.Results showed that the minimum inhibition concentrations of acetic acid,lactic acid,and butyric acid were 2560μg/mL,and the minimum inhibition concentrations of citric acid and malic acid were 5120μg/mL;The median effective concentrations of acetic acid,lactic acid,butyric acid,citric acid,and malic acid were 1004.90,1497.50,964.32,1406.02,and 1727.72μg/mL,respectively.The combination of acetic acid and lactic acid showed additivity,and the combinations of acetic acid,lactic acid,and a third organic acid(butyric acid,citric acid,and malic acid)showed synergism.Organic acids and their combinations have caused a decrease in the membrane potential of E.coli,and most of the organisms showed shrinkage and bending deformation.