抗菌肽与抗生素的体外抗菌效果比较

应用由 Hancock实验室改进的微量肉汤稀释法测定了 cecropin P1、cecropin A、magainin 2、defensin 1、bactenecin、lactoferricin和 indolicidin等 7种抗菌肽和盐酸金霉素、去甲万古霉素、土霉素、强力霉素等 4种抗生素的体外抗菌活性 ,并且使用薄层琼脂糖孔穴扩散法比较了抗菌肽中 cecropin P1和 cecropin A与土霉素和呋喃唑酮对大肠杆菌 K88的抑菌效果。结果发现 ,抗菌肽与抗生素一样对几种革兰氏阳性菌和阴性菌都有不同程度的抗菌效果。其中 cecropin A、cecropin P1和 defensin1对大肠杆菌的 2个菌株 ATCC2 5 92 2和 K88的抗菌活性高于抗生素 ,defensin1是各种抗菌肽中对金黄色葡萄球菌抗菌效果最好的。抗生素对试验用金黄色葡萄球菌的抑制活性总体上要好于抗菌肽。与抗生素相比 ,cecropin A、cecropin P1和 indolicidin对猪霍乱沙门氏菌和鼠伤寒沙门氏菌具有更好的抗菌效果。另外 ,抗菌肽的抑菌圈边缘十分清晰 ,而抗生素的整个抑菌圈都比较模糊且界线不明。因此 ,从抗菌效果方面考虑 ,抗菌肽可以代替抗生素用于疾病的预防和治疗

Comparison of Antimicrobial Activity in Vitro of Antimicrobial Peptides and Antibiotics against Gram-positive and Gramnegative Bacteria

The in vitro susceptibilities of seven antimicrobial cationic peptides:lactoferricin,bactenecin,magainin 2,cecropin P1,cecropin A,indolicidin and defensin 1,and four clinically used antibiotics:chlortetracycline hydrochloride,demethylvancomycin,oxytetracycline and doxycycline,were evaluated against several Gram-positive and Gram-negative aerobic bacteria,using modified broth microdilution method by Hancock Laboratory.The tested cationic peptides showed different antimicrobial activities against the bacteria like antibiotics.Two strains of E.coli ATCC 25922 and K88 were more susceptible to antimicrobial peptides,especially to cecropin A and cecropin P1,whereas antibiotics exhibited higher activity against Gram-positive bacteria Staphylococcus aureus than all peptides.Defensin 1 was the most active compound against Staphylococcus aureus among all tested peptides.In addition,cecropin A and cecropin P1 revealed a stronger inhibitory effect on Salmonella chloleraesuis than S.typhimurium.In contrast to the ones of antibiotics,the zones of inhibition of antimicrobial peptides are clearer,and the edge is sharper.Considering the antimicrobial activity,antimicrobial peptides are regarded as attractive substitute drugs in the prevention and treatment of bacteric infections.