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目的通过对一株植物乳杆菌代谢产物的抑菌作用以及该产物的某些物理特性的研究,为进一步发现可替代现有抗生素的抗菌物质奠定基础。方法首先利用低温离心和超滤法对植物乳杆菌培养后的上清液进行初步提取,用打孔法行抑菌试验,明确其对铜绿假单胞菌、大肠埃希菌、肺炎克雷伯菌和金黄色葡萄球菌等临床分离菌株的抑菌活性;并进一步经加热、调整pH及过氧化氢酶等处理上清液后,再验证其活性变化。结果植物乳杆菌的培养上清液对铜绿假单胞菌等多株临床分离菌株均具有一定的抑菌活性,且以pH在6以内时该物质抑菌活性较好,过氧化氢酶处理后或加热至100℃、30min,上清液的抑菌活性依然存在。结论在植物乳杆菌的培养上清液中存在着具有抑菌活性的物质,对从临床标本所分离的部分革兰阴性菌及革兰阳性菌有抑菌作用,该物质对热耐受,其活性受pH变化的影响。
OBJECTIVE To study the antibacterial activity of a Lactobacillus plantarum metabolite and to study some physical properties of the product, and to lay the foundation for further discovering antibacterial substances that can substitute existing antibiotics. Methods The supernatant of Lactobacillus plantarum was initially extracted by low temperature centrifugation and ultrafiltration. The antibacterial activity of the supernatant of Lactobacillus plantarum was determined by perforated method. The results showed that the supernatant of Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Bacteria and Staphylococcus aureus and other clinical isolates of antibacterial activity; and further by heating, adjusting the pH and catalase treatment supernatant, and then verify the changes in its activity. Results The culture supernatant of Lactobacillus plantarum had some antibacterial activities against many strains of clinical isolates such as Pseudomonas aeruginosa and the antibacterial activity was better when the pH value was within 6. After the catalase treatment Or heated to 100 ℃, 30min, the antibacterial activity of the supernatant still exists. Conclusion There are antibacterial substances in the culture supernatant of Lactobacillus plantarum, which have antibacterial activity against some Gram-negative bacteria and Gram-positive bacteria isolated from clinical specimens. Activity is affected by changes in pH.