Role of the cell envelope in the antibacterial activities of polymyxin B and polymyxin B nonapeptide against Escherichia coli

Dixon, Ron and Sahalan, Ahmad Z. (2008) Role of the cell envelope in the antibacterial activities of polymyxin B and polymyxin B nonapeptide against Escherichia coli. International Journal of Antimicrobial Agents , 31 (3). pp. 224-227. ISSN 0924-8579

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Full text URL: http://dx.doi.org/10.1016/j.ijantimicag.2007.10.00...

Abstract

The role of membrane permeabilisation and disruption in the mechanism of action of some polymyxin analogues against Gram-negative organisms is contentious. The effects of polymyxin B (PMB) and its analogue polymyxin B nonapeptide (PMBN) on Escherichia coli envelopes should correlate, but previous work by other workers suggests that PMBN has a different mode of action. This study has reassessed the biochemical techniques used previously and has shown that, in contrast to previous studies, PMBN (a well-characterised antibacterial synergist) readily releases periplasmic proteins and lipopolysaccharide from treated E. coli at subinhibitory concentrations in normal physiological buffer conditions. We conclude that, when tested with appropriate methodology, PMBN closely correlates with the early effects of PMB on the cell envelope of E. coli and this study shows that it is now consistent with the accepted interactions of membrane-active agents against Gram-negative cells.

Item Type:Article
Keywords:escherichia coli, polymyxin nonapeptide, polymyxin, bacterial membranes, mode of action
Subjects:C Biological Sciences > C521 Medical Microbiology
C Biological Sciences > C500 Microbiology
Divisions:College of Science > School of Life Sciences
ID Code:2659
Deposited By: Ron Dixon
Deposited On:11 Jun 2010 08:57
Last Modified:06 Dec 2013 08:41

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