FLOW CYTOMETRIC ANALYSIS OF CHLORHEXIDINE ACTION

The mechanism by which chlorhexidine kills bacteria is still ill defin ed. We have investigated the action of chlorhexidine on Escherichia co li JM101/psb311 using a combination of flow cytometry and traditional methods. Chlorhexidine-induced uptake by E. coli cells of bis-(1,3-dib utylbarturic acid) trimethine oxonol and propidium iodide, which monit or membrane potential and membrane integrity respectively, was shown t o be concentration dependent for the range 0.003-0.3 mmol(-1), In addi tion, cells in log phase growth were more susceptible to 0.03 mmol(-1) chlorhexidine than those in stationary phase. There was, however, no direct correlation between dye uptake and decline in colony forming un its.