Heterogeneity in ess transcriptional organization and variable contribution of the Ess/Type VII protein secretion system to virulence across closely related Staphylocccus aureus strains. Issue 5 (30th July 2014)

• Record Type: Journal Article
• Authors: Kneuper, Holger; Cao, Zhen Ping; Twomey, Kate B.; Zoltner, Martin; Jäger, Franziska; Cargill, James S.; Chalmers, James; van der Kooi‐Pol, Magdalena M.; van Dijl, Jan Maarten; Ryan, Robert P.; Hunter, William N.; Palmer, Tracy
• Is Part Of: Molecular microbiology. Volume 93:Issue 5(2014)
• Page Start: 928
• Page End: 943
• Publication Date: 2014-07-30
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12707
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>The Type VII protein secretion system, found in Gram‐positive bacteria, secretes small proteins, containing a conserved W‐x‐G amino acid sequence motif, to the growth medium. <italic>S</italic><italic>taphylococcus aureus</italic> has a conserved Type VII secretion system, termed Ess, which is dispensable for laboratory growth but required for virulence. In this study we show that there are unexpected differences in the organization of the <italic>ess</italic> gene cluster between closely related strains of <italic>S</italic>. <italic>aureus</italic>. We further show that in laboratory growth medium different strains of <italic>S</italic>. <italic>aureus</italic> secrete the EsxA and EsxC substrate proteins at different growth points, and that the Ess system in strain Newman is inactive under these conditions. Systematic deletion analysis in <italic>S</italic>. <italic>aureus</italic> RN6390 is consistent with the EsaA, EsaB, EssA, EssB, EssC and EsxA proteins comprising core components of the secretion machinery in this strain. Finally we demonstrate that the Ess secretion machinery of two <italic>S</italic>. <italic>aureus</italic> strains, RN6390 and COL, is important for nasal colonization and virulence in the murine lung pneumonia model. Surprisingly, however, the secretion system plays no role in the virulence of strain SA113 under the same conditions.</p> </abstract>