SigB is a dominant regulator of virulence in Staphylococcus aureus small-colony variants.

Staphylococcus aureus small-colony variants (SCVs) are persistent pathogenic bacteria characterized by slow growth and, for many of these strains, an increased ability to form biofilms and to persist within host cells. The virulence-associated gene expression profile of SCVs clearly differs from tha...

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Main Authors: Gabriel Mitchell, Alexandre Fugère, Karine Pépin Gaudreau, Eric Brouillette, Eric H Frost, André M Cantin, François Malouin
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3660380?pdf=render
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author Gabriel Mitchell
Alexandre Fugère
Karine Pépin Gaudreau
Eric Brouillette
Eric H Frost
André M Cantin
François Malouin
author_facet Gabriel Mitchell
Alexandre Fugère
Karine Pépin Gaudreau
Eric Brouillette
Eric H Frost
André M Cantin
François Malouin
author_sort Gabriel Mitchell
collection DOAJ
description Staphylococcus aureus small-colony variants (SCVs) are persistent pathogenic bacteria characterized by slow growth and, for many of these strains, an increased ability to form biofilms and to persist within host cells. The virulence-associated gene expression profile of SCVs clearly differs from that of prototypical strains and is often influenced by SigB rather than by the agr system. One objective of this work was to confirm the role of SigB in the control of the expression of virulence factors involved in biofilm formation and intracellular persistence of SCVs. This study shows that extracellular proteins are involved in the formation of biofilm by three SCV strains, which, additionally, have a low biofilm-dispersing activity. It was determined that SigB activity modulates biofilm formation by strain SCV CF07-S and is dominant over that of the agr system without being solely responsible for the repression of proteolytic activity. On the other hand, the expression of fnbA and the control of nuclease activity contributed to the SigB-dependent formation of biofilm of this SCV strain. SigB was also required for the replication of CF07-S within epithelial cells and may be involved in the colonization of lungs by SCVs in a mouse infection model. This study methodically investigated SigB activity and associated mechanisms in the various aspects of SCV pathogenesis. Results confirm that SigB activity importantly influences the production of virulence factors, biofilm formation and intracellular persistence for some clinical SCV strains.
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spelling doaj.art-71d369ab7d674af58159b45cf201bbd52022-12-22T02:36:00ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0185e6501810.1371/journal.pone.0065018SigB is a dominant regulator of virulence in Staphylococcus aureus small-colony variants.Gabriel MitchellAlexandre FugèreKarine Pépin GaudreauEric BrouilletteEric H FrostAndré M CantinFrançois MalouinStaphylococcus aureus small-colony variants (SCVs) are persistent pathogenic bacteria characterized by slow growth and, for many of these strains, an increased ability to form biofilms and to persist within host cells. The virulence-associated gene expression profile of SCVs clearly differs from that of prototypical strains and is often influenced by SigB rather than by the agr system. One objective of this work was to confirm the role of SigB in the control of the expression of virulence factors involved in biofilm formation and intracellular persistence of SCVs. This study shows that extracellular proteins are involved in the formation of biofilm by three SCV strains, which, additionally, have a low biofilm-dispersing activity. It was determined that SigB activity modulates biofilm formation by strain SCV CF07-S and is dominant over that of the agr system without being solely responsible for the repression of proteolytic activity. On the other hand, the expression of fnbA and the control of nuclease activity contributed to the SigB-dependent formation of biofilm of this SCV strain. SigB was also required for the replication of CF07-S within epithelial cells and may be involved in the colonization of lungs by SCVs in a mouse infection model. This study methodically investigated SigB activity and associated mechanisms in the various aspects of SCV pathogenesis. Results confirm that SigB activity importantly influences the production of virulence factors, biofilm formation and intracellular persistence for some clinical SCV strains.http://europepmc.org/articles/PMC3660380?pdf=render
spellingShingle Gabriel Mitchell
Alexandre Fugère
Karine Pépin Gaudreau
Eric Brouillette
Eric H Frost
André M Cantin
François Malouin
SigB is a dominant regulator of virulence in Staphylococcus aureus small-colony variants.
PLoS ONE
title SigB is a dominant regulator of virulence in Staphylococcus aureus small-colony variants.
title_full SigB is a dominant regulator of virulence in Staphylococcus aureus small-colony variants.
title_fullStr SigB is a dominant regulator of virulence in Staphylococcus aureus small-colony variants.
title_full_unstemmed SigB is a dominant regulator of virulence in Staphylococcus aureus small-colony variants.
title_short SigB is a dominant regulator of virulence in Staphylococcus aureus small-colony variants.
title_sort sigb is a dominant regulator of virulence in staphylococcus aureus small colony variants
url http://europepmc.org/articles/PMC3660380?pdf=render
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