Koga T, Watanabe H, Kawada H, Takahashi K, Utsui Y, Domon H, Ishii C, Narita T, Yasuda H
Biological Research Laboratories, Sankyo Co., Ltd, Tokyo, Japan.
J Antimicrob Chemother. 1998 Aug;42(2):133-40. doi: 10.1093/jac/42.2.133.
Plaunotol, a cytoprotective antiulcer agent, has a bactericidal effect against Helicobacter pylori, which may result from interaction of this compound with the bacterial cell membrane. The purpose of the present study was to confirm that plaunotol interacts with the H. pylori membrane. Membrane fluidities were measured using two stearic acid spin labels, namely 5-doxyl-stearic acid (in which the nitroxide group is located in the upper portion of the bacterial cell membrane) and 16-doxyl-stearic acid methyl ester (in which the nitroxide group is located deeper in the bacterial cell membrane), by means of electron spin resonance. The membrane fluidities of plaunotol-treated cells were significantly increased in the measurements made using the two spin labels. We also attempted to isolate plaunotol-resistant H. pylori in vitro by two different methods. To assess the level of resistance that could be reached, H. pylori was passaged five times on an agar plate containing subinhibitory concentrations of plaunotol or metronidazole. To measure the rate of development of resistance, H. pylori was grown with subinhibitory concentrations (0.25 x MIC) of plaunotol or metronidazole, and quantitatively plated on to medium containing 4 x MIC of the compounds. This treatment was repeated once more. No plaunotol-resistant colonies were selected by the two methods. H. pylori developed resistance to metronidazole easily and at a relatively high rate. The mechanism by which plaunotol directly fluidizes and destroys the H. pylori membrane might make it difficult for this organism to develop resistance to plaunotol. It was confirmed that the bactericidal effects of plaunotol were also shown against Staphylococcus aureus, Streptococcus pneumoniae, Neisseria gonorrhoeae, Moraxella catarrhalis and Haemophilus influenzae. No such effect was seen against Escherichia coli and Pseudomonas aeruginosa.
普劳诺托是一种具有细胞保护作用的抗溃疡药物，对幽门螺杆菌具有杀菌作用，这可能是该化合物与细菌细胞膜相互作用的结果。本研究的目的是证实普劳诺托与幽门螺杆菌膜相互作用。通过电子自旋共振，使用两种硬脂酸自旋标记物，即5-脱氧硬脂酸（其中氮氧基团位于细菌细胞膜的上部）和16-脱氧硬脂酸甲酯（其中氮氧基团位于细菌细胞膜的较深处）来测量膜流动性。在使用这两种自旋标记物进行的测量中，普劳诺托处理的细胞的膜流动性显著增加。我们还尝试通过两种不同的方法在体外分离对普劳诺托耐药的幽门螺杆菌。为了评估可能达到的耐药水平，将幽门螺杆菌在含有亚抑制浓度的普劳诺托或甲硝唑的琼脂平板上传代五次。为了测量耐药性的发展速率，将幽门螺杆菌在含有亚抑制浓度（0.25×最低抑菌浓度）的普劳诺托或甲硝唑的条件下培养，并定量接种到含有4×最低抑菌浓度的这些化合物的培养基上。该处理再重复一次。通过这两种方法均未筛选出对普劳诺托耐药的菌落。幽门螺杆菌很容易且以相对较高的速率对甲硝唑产生耐药性。普劳诺托直接使幽门螺杆菌膜流动性增加并破坏其膜的机制可能使该生物体难以对普劳诺托产生耐药性。已证实普劳诺托对金黄色葡萄球菌、肺炎链球菌、淋病奈瑟菌、卡他莫拉菌和流感嗜血杆菌也有杀菌作用。对大肠杆菌和铜绿假单胞菌未见此作用。
