不同抗生素杀菌过程导致细菌内毒素释放的异质性

目的初步了解各类抗生素杀菌过程导致细菌内毒素释放的不同特点。方法采用鲎基质偶氮法检测各类不同抗生素２倍最低抑菌浓度下对大肠埃希氏菌杀菌时细菌内毒素的释放量，计算杀菌开始至活菌数基本稳定阶段，平均每减少１个对数数量级（ｌｇ）菌落形成单位（ＣＦＵ）所导致的内毒素释放量（杀菌释放率）。结果各类抗生素致内毒素释放能力大致可以分为低、中、高三类，杀菌释放率的界限值分别为１０ｎｇ／ｉｇＣＦＵ和３０ｎｇ／ｉｇＣＦＵ。多粘菌素Ｂ具有低于所有品种的释放率。β－内酰胺类抗生素中的羟氨苄青霉素、棒酸和亚胺硫霉素具低释放率，氨苄青霉素、头孢氨苄、头孢呋辛、头孢哌酮、头孢他啶、氨曲南具高释放率。喹诺酮类的环丙沙星具高释放率，氧氟沙星具中等释放率。氨基甙类均具中等释放率，品种间无显著差异。此外，磷霉素也具有中等释放率。结论具有相似临床杀菌作用的抗生素可以具有差异明显的致内毒素释放能力，此认识有助于指导全身炎症反应综合征时抗生素的选择

The diverse characteristics of endotoxin release by differential antibiotic killing of bacteria

OBJECTIVE To investigate the characteristics of endotoxin release induced by differential antibiotic killing of bacteria was studied. METHODS The endotoxin-liberating quantity were measured by a chromogenic limulus amebocyte lysate test in the 2 times minimal inhibitory concentration (MIC) of antibiotics killing process of Escherichia coli. The endotoxin release quantity induced by average one-lg decrease in numbers of colony forming units (CFU) was calculated. RESULTS The release rate of antibiotics can be divided into low, middle, high types. The dividing lines of release rate were 10ng/lg cfu and 30ng/lg cfu. Polymycin B has the lowest release rate among all antibiotics. Beta-lactam amoxacillin, clavulanic acid and imipenem belong to low type. Beta-lactam ampicillin, cephalexin, cefuroxime, cefoperazone, ceftazidime and aztronam belong to high type. Quinolomes ciprofloxacin belong to high type, but ofloxacin belong to middle type. There were no obvious difference among aminoglgcoside, all of them belong to middle type. Fosfomycin also belong to middle type. CONCLUSION The antibiotics which have same antibacterial effect may have obvious differential endotoxin-liberating potential. This understanding is helpful to select antibiotics in systemic inflammatory response syndrome(SIRS).