Fan Frank, Yan Kang, Wallis Nicola G, Reed Shannon, Moore Terrance D, Rittenhouse Stephen F, DeWolf Walter E, Huang Jianzhong, McDevitt Damien, Miller William H, Seefeld Mark A, Newlander Kenneth A, Jakas Dalia R, Head Martha S, Payne David J
Microbial, Musculoskeletal and Proliferative Diseases CEDD. Computational and Structural Sciences, GlaxoSmithKline Pharmaceuticals, Collegeville, Pennsylvania 19426, USA.
Antimicrob Agents Chemother. 2002 Nov;46(11):3343-7. doi: 10.1128/AAC.46.11.3343-3347.2002.
The MICs of triclosan for 31 clinical isolates of Staphylococcus aureus were 0.016 micro g/ml (24 strains), 1 to 2 micro g/ml (6 strains), and 0.25 micro g/ml (1 strain). All the strains for which triclosan MICs were elevated (>0.016 micro g/ml) showed three- to fivefold increases in their levels of enoyl-acyl carrier protein (ACP) reductase (FabI) production. Furthermore, strains for which triclosan MICs were 1 to 2 micro g/ml overexpressed FabI with an F204C alteration. Binding studies with radiolabeled NAD(+) demonstrated that this change prevents the formation of the stable triclosan-NAD(+)-FabI complex, and both this alteration and its overexpression contributed to achieving MICs of 1 to 2 micro g/ml for these strains. Three novel, potent inhibitors of FabI (50% inhibitory concentrations, < or =64 nM) demonstrated up to 1,000-fold better activity than triclosan against the strains for which triclosan MICs were elevated. None of the compounds tested from this series formed a stable complex with NAD(+)-FabI. Consequently, although the overexpression of wild-type FabI gave rise to an increase in the MICs, as expected, overexpression of FabI with an F204C alteration did not cause an additional increase in resistance. Therefore, this work identifies the mechanisms of triclosan resistance in S. aureus, and we present three compounds from a novel chemical series of FabI inhibitors which have excellent activities against both triclosan-resistant and -sensitive clinical isolates of S. aureus.
三氯生对31株金黄色葡萄球菌临床分离株的最低抑菌浓度（MIC）分别为0.016μg/ml（24株）、1至2μg/ml（6株）和0.25μg/ml（1株）。所有三氯生MIC升高（>0.016μg/ml）的菌株，其烯酰-酰基载体蛋白（ACP）还原酶（FabI）的产生水平增加了三至五倍。此外，三氯生MIC为1至2μg/ml的菌株过度表达了带有F204C改变的FabI。用放射性标记的NAD(+)进行的结合研究表明，这种变化阻止了稳定的三氯生-NAD(+)-FabI复合物的形成，这种改变及其过度表达都导致这些菌株的MIC达到1至2μg/ml。三种新型强效FabI抑制剂（50%抑制浓度，≤64 nM）对三氯生MIC升高的菌株表现出比三氯生高1000倍的活性。该系列测试的化合物均未与NAD(+)-FabI形成稳定复合物。因此，尽管野生型FabI的过度表达导致MIC增加，但正如预期的那样，带有F204C改变的FabI过度表达并未导致耐药性进一步增加。因此，这项工作确定了金黄色葡萄球菌对三氯生耐药的机制，并且我们展示了来自新型化学系列FabI抑制剂的三种化合物，它们对金黄色葡萄球菌的三氯生耐药和敏感临床分离株均具有优异的活性。
