大环内酯类、氨基糖苷类抗生素.ppt

Protein synthesis inhibitors (PSI)
Antibacterial Agents II
MAJOR CLASSES OF PROTEIN SYNTHESIS INHIBITORS
Aminoglycosides - BACTERICIDAL
Macrolides大环内酯类
Clindamycin 林可霉素
Tetracyclines
Chloramphenicol
BACRTERIOSTATIC
Mechanism of action of PSI and modes of microbial resistance
PSIs interfere with different steps in protein synthesis
氨基糖苷类抗生素
Aminoglycosides
氨基糖苷类抗生素共性
化学结构相似
不良反应相似
抗菌原理相似
体内过程相似
抗菌谱相似
链霉素(streptomycin)
(美板培养皿中生长霉菌含有天然的抗生素----- 链霉素,它是在土壤中发现的(1943年)
The first randomized trial of streptomycin against pulmonary tuberculosis was carried out in 1946-1947.
The trial was both double-blind and placebo-controlled.
It is widely accepted to have been the first randomised curative trial.
抗菌作用机制
氨基糖苷类抗生素的抗菌机制主要是抑制细菌蛋白质合成,还能破坏细菌胞浆膜的完整性。
①在起始阶段:
②在肽链延伸阶段:
③在终止阶段:
氨基糖苷类药物的抗菌机制示意图
特点(characteristics)
氨基糖苷抗生素类是快速杀菌药,对静止期细菌有较强作用。杀菌特点是:
Single large dose
Multiple small doses
Time
Efficacy of drug
MIC
①杀菌速率和杀菌持续时间与浓度呈正相关;
②仅对需氧菌有效,对厌氧菌无效;
③具有抗生素后效应;
④在碱性环境中抗菌活性增强。