The outer membrane permeability-increasing action of deacylpolymyxins

Abstract

The outer membrane permeability-increasing action of deacylpolymyxins was compared to the well-known potent action of polymyxin B nonapeptide (PMBN). Deacylpolymyxin B (DAPB), prepared by treating polymyxin B with polymyxin acylase, was found to be a slightly more effective permeabilizer than PMBN. As low a DAPB concentration as 1 μg/ml sensitized Escherichia coli to the probe antibiotics (rifampin, fusidic acid, erythromycin, clindamycin, novobiocin) by factors 30~ 100 and Salmonella typhimurium by factors 10~ 100. A higher concentration (3 μg/ml) of DAPB elicited further sensitization. Also deacylcolistin (DAC) was found to be an effective permeabilizer. © 1991, JAPAN ANTIBIOTICS RESEARCH ASSOCIATION. All rights reserved.