大肠杆菌、金黄色葡萄球菌对利福定耐药与包膜屏障改变的关系

RELATIONSHIP BETWEEN BACTERIAL ENVELOPE BARRIER AND RESISTANCE OF E.coli,S.aureus TO RIFANDINE

选用金黄色葡萄球菌、大肠杆菌及变形杆菌敏感株,经药物梯度平皿筛选得到耐药性突变株,测定细菌生长浊度变化。以利福定(RFD)或EDTA分别作用时,耐药菌的生长曲线不受影响,RFD和EDTA合用,则耐药菌的生长曲线受到明显抑制。以~3H-RFD分别掺入敏感菌及耐药菌,前者的药物掺入量明显高于后者。电镜观察见耐药菌菌体变得粗短,表面粗糙,外膜增厚,膜皱折增多。以上结果提示,细菌包膜屏障在耐药性产生中具有重要作用。

The Rifandine (RFD) resistant strainswere obtained from wild types of S. aureusNCTC 6571, E. coli NCTC 10418 and Proteusvulgaris by drug concentration gradientplate.The experiment indicated that thegrowth inhibition of resistant cells inducedby synergism of EDTA acting with RFD.Such results did not occur effectively ifEDTA or RFD was added separately. Theamount of ~8H-RFD incorporated into cellsof susceptible and resistant strains of E.coliand S.aureus was compared. The amountof ~8H-RFD incorporated into susceptiblecells was much greater than that of theresistant strains in E.coli cells. Ultrastruc-ture comparison of sensitive and resistantcells showed that the surface of resistantcells was coarser and shorter, the outermembrane thickened and electron densityincreased. These results have shown that there isa close relationship between the resistanceof bacteria induced by RFD and the de-crease in the permeability of cell envelopebarrier to the drug.