细菌对利福定的耐药性与细菌包膜屏障的关系

选用大肠杆菌k-12及其耐利福定菌株,利用同位素示踪技术研究发现利福定明显抑制~3H-尿苷掺入敏感菌,而耐药菌掺入则不受抑制,加用膜通透剂EDTA后,~3H-尿苷掺入耐药菌受到明显的抑制;~3H-利福定透入耐药菌的量明显低于透入敏感菌的量,用EDTA后,透入耐药菌中的~3H-利福定显著增加。结果提示:细菌包膜屏障通透性降低使药物进入菌体减少是细菌对利福定耐药的重要机制之一。

STUDIES ON THE RELATIONSHIP BETWEEN THE BACTERIAL ENVELOPE BARRIER AND THE RESISTANCE INDUCED BY RIFANDIN

The relationship between the bacterial resistance to rifandin (RFD, R76-1) and the cell envelope barrier was investigated. The RFD-resis-tant strain was induced from wild type of Escherichia coli k-12 by using RFD concentration gradient plates. The incorporation of ~3H-UR into the susceptible strain was significantly inhibited by RFD and by tie conbination of RFD and EDTA. RFD failed to inhibit the incorporation of ~3H-UR into the resistant strain, but with addition EDTA the incorporation was inhibited by RFD. The amount of ~3H-RFD incorporated into the susceptible strain was much higher than that of the resistant strain. Also ~3H-RFD incorporated into the resistant strain increased rapidly if EDTA was used. Our results showed that one of the resistant mechanism to RFD is refer-ed to a decrease of the permeability of bacterial envelope barrier.