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Staphylococcal Phenotypes Induced by Naturally Occurring and Synthetic Membrane-Interactive Polyphenolic β-Lactam Resistance Modifiers

Title: Staphylococcal Phenotypes Induced by Naturally Occurring and Synthetic Membrane-Interactive Polyphenolic β-Lactam Resistance Modifiers
Author(s): Palacios, L
Rosado, H
Micol, V
Rosato, AE
Bernal, P
Arroyo, R
Grounds, H
Anderson, JC
Stabler, RA
Taylor, PW
Item Type: Journal Article
Abstract: Galloyl catechins, in particular (-)-epicatechin gallate (ECg), have the capacity to abrogate β-lactam resistance in methicillin-resistant strains of Staphylococcus aureus (MRSA); they also prevent biofilm formation, reduce the secretion of a large proportion of the exoproteome and induce profound changes to cell morphology. Current evidence suggests that these reversible phenotypic traits result from their intercalation into the bacterial cytoplasmic membrane. We have endeavoured to potentiate the capacity of ECg to modify the MRSA phenotype by stepwise removal of hydroxyl groups from the B-ring pharmacophore and the A:C fused ring system of the naturally occurring molecule. ECg binds rapidly to the membrane, inducing up-regulation of genes responsible for protection against cell wall stress and maintenance of membrane integrity and function. Studies with artificial membranes modelled on the lipid composition of the staphylococcal bilayer indicated that ECg adopts a position deep within the lipid palisade, eliciting major alterations in the thermotropic behaviour of the bilayer. The non-galloylated homolog (-)-epicatechin enhanced ECg-mediated effects by facilitating entry of ECg molecules into the membrane. ECg analogs with unnatural B-ring hydroxylation patterns induced higher levels of gene expression and more profound changes to MRSA membrane fluidity than ECg but adopted a more superficial location within the bilayer. ECg possessed a high affinity for the positively charged staphylococcal membrane and induced changes to the biophysical properties of the bilayer that are likely to account for its capacity to disperse the cell wall biosynthetic machinery responsible for β-lactam resistance. The ability to enhance these properties by chemical modification of ECg raises the possibility that more potent analogs could be developed for clinical evaluation.
Publication Date: 3-Apr-2014
Date of Acceptance: 7-Mar-2014
URI: http://hdl.handle.net/10044/1/42408
DOI: http://dx.doi.org/10.1371/journal.pone.0093830
ISSN: 1932-6203
Publisher: Public Library of Science
Journal / Book Title: PLOS One
Volume: 9
Issue: 4
Copyright Statement: © 2014 Palacios et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Keywords: Anti-Bacterial Agents
Cell Wall
Drug Resistance, Bacterial
Gene Expression Regulation, Bacterial
Methicillin-Resistant Staphylococcus aureus
Microbial Sensitivity Tests
Phenotype
Cell Wall
Anti-Bacterial Agents
Microbial Sensitivity Tests
Drug Resistance, Bacterial
Gene Expression Regulation, Bacterial
Phenotype
Methicillin-Resistant Staphylococcus aureus
General Science & Technology
MD Multidisciplinary
Publication Status: Published
Article Number: e93830
Appears in Collections:Faculty of Natural Sciences



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