青霉素类2.ppt
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1、 -内酰胺类抗生素内酰胺类抗生素-Lactam antibiotics are useful and frequently prescribed antibiotics that share a common structure and mechanism of actioninhibition of synthesis of the bacterial peptidoglycan cell wall.CNHCHCHCOOCNCHCH3CH3COOHSSite of penicillinase action.Breakage of the lactam ring.STRUCTURE OF PE
2、NICILLINsubstituentsRNucleus 6-aminopenicillanic acid(6-APA)6-氨基青霉烷酸AB分分 类类青霉素类青霉素类Penicillins :天然青霉素、半合成青霉素天然青霉素、半合成青霉素头孢菌素类头孢菌素类Cephalosporins :一、二、三、四一、二、三、四代代非典型的非典型的-内酰胺类内酰胺类Other-Lactam Antibiotics:头霉素类头霉素类 氧头孢烯类氧头孢烯类 碳青霉烯类碳青霉烯类 单环单环-内酰胺类内酰胺类 -内酰胺酶抑制药内酰胺酶抑制药抗菌作用机制抗菌作用机制抗菌机制抗菌机制 作用靶点:作用靶点:黏肽合成酶
3、黏肽合成酶青霉素结合蛋白(青霉素结合蛋白(PBPsPBPs)PBPsPBPs分类:分类:PBP-1PBP-1,PBP-2PBP-2,PBP-3,PBP-4PBP-3,PBP-4 与细菌形态和功能相关,维持与细菌形态和功能相关,维持 细菌生命必需细菌生命必需 抗菌机制抗菌机制抑制细菌细胞壁抑制细菌细胞壁PBPsPBPs活性,阻碍细胞壁合成,使细活性,阻碍细胞壁合成,使细胞壁缺损,水分渗入,菌体膨胀裂解胞壁缺损,水分渗入,菌体膨胀裂解触发细菌自溶酶,使细菌裂解溶化触发细菌自溶酶,使细菌裂解溶化 与与PBP3结合,结合,阻碍细菌分裂繁殖,菌体出现形态、功能异阻碍细菌分裂繁殖,菌体出现形态、功能异常常
4、耐药机制耐药机制 产生水解酶产生水解酶 窄谱酶:仅能水解青霉素或头孢菌素窄谱酶:仅能水解青霉素或头孢菌素 广谱酶:水解青霉素和头孢菌素广谱酶:水解青霉素和头孢菌素 超广谱酶超广谱酶 (ESBLs):水解第三代头孢菌素和单环:水解第三代头孢菌素和单环-内酰胺内酰胺类类克雷伯肺炎杆菌和肠杆菌属产生克雷伯肺炎杆菌和肠杆菌属产生 改变靶位结构改变靶位结构 耐甲氧西林葡萄球菌耐甲氧西林葡萄球菌(Methicillin-Resistant S.Aureus/Epidermidis,MRSA/MRSE)多一个PBP-2a,其功能相当于敏感金葡菌全部主要PBPs的功能,并且与抗生素结合的亲和力极低,因而细菌对
5、万古霉素以外几乎所有常用抗生素都耐药。青霉素类抗生素青霉素类抗生素A tale by A.Fleming He took a sample of the mold from the contaminated plate.He found that it was from the penicillium family,later specified as Penicillium notatum.Fleming presented his findings in 1929,but they raised little interest.He published a report on penici
6、llin and its potential uses in the British Journal of Experimental Pathology.http:/ by musicologists use of fragmented scores to complete the unfinished works of great composers,a British researcher has pieced together Alexander Flemings laboratory scribblings to recreate a paper that he says restor
7、es the reputation of the much-maligned discoverer of penicillin.链球菌链球菌青霉素青霉素Thanks to work by Alexander Fleming(1881-1955),Howard Florey(1898-1968)and Ernst Chain(1906-1979),penicillin was first produced on a large scale for human use in 1943.At this time,the development of a pill that could reliabl
8、y kill bacteria was a remarkable development and many lives were saved during World War II because this medication was available.E.Chain H.FloreyA.FlemingFor lecture only,BC Yang1928年年Alexander Fleming1940年年 Chain and Florey1945年年 the Nobel prize 50年代末年代末 半合成青霉素半合成青霉素NSHNCCOOOHORCH3CH36-APA分分 类类天然青霉
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