EFFECT OF POLYMYXIN-B ON OUTER MEMBRANES OF SERRATIA-MARCESCENS - MORPHOLOGICAL ALTERATIONS OF OUTER MEMBRANES AND THEIR LIPOPOLYSACCHARIDE COMPONENTS

  • 1 January 1976
    • journal article
    • research article
    • Vol. 17  (68-6) , 149-161
Abstract
The in vitro or the in vivo treatment of outer membranes and their lipopolysaccharide (LPS) components from S. marcescens with the antibiotic polymyxin B appeared to alter their normal morphology in a sequential manner. The normal spheroidal morphology was destabilized into a flattened structure after the in vitro treatment of either the resistant strain O8 or the sensitive strain Bizio. The more severe in vivo treatment of the outer membranes from the resistant strain converted the flattened forms further into spheres with undefined periphery and diminished sizes. The same treatment of the outer membranes from the sensitive strain resulted in numerous incomplete spheres and short rods, which were similar to the various morphological forms of the LPS components after polymyxin B treatment. The difference in the morphological changes of the outer membranes and their LPS components of the resistant and sensitive strains after polymyxin B treatment may be explained by the variation of the susceptibility of the membrane components to the degradative effects of the antibiotic.