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Alpha-Toxin Promotes Staphylococcus aureus Mucosal Biofilm Formation
Journal article   Open access   Peer reviewed

Alpha-Toxin Promotes Staphylococcus aureus Mucosal Biofilm Formation

Michele J Anderson, Ying-Chi Lin, Aaron N Gillman, Patrick J Parks, Patrick M Schlievert and Marnie L Peterson
Frontiers in cellular and infection microbiology, Vol.2, pp.64-64
2012
DOI: 10.3389/fcimb.2012.00064
PMCID: PMC3417397
PMID: 22919655
url
https://doi.org/10.3389/fcimb.2012.00064View
Published (Version of record) Open Access

Abstract

Staphylococcus aureus causes many diseases in humans, ranging from mild skin infections to serious, life-threatening, superantigen-mediated Toxic Shock Syndrome (TSS). S. aureus may be asymptomatically carried in the anterior nares or vagina or on the skin, serving as a reservoir for infection. Pulsed-field gel electrophoresis clonal type USA200 is the most widely disseminated colonizer and the leading cause of TSS. The cytolysin α-toxin (also known as α-hemolysin or Hla) is the major epithelial proinflammatory exotoxin produced by TSS S. aureus USA200 isolates. The current study aims to characterize the differences between TSS USA200 strains [high ( hla + ) and low ( hla − ) α-toxin producers] in their ability to disrupt vaginal mucosal tissue and to characterize the subsequent infection. Tissue viability post-infection and biofilm formation of TSS USA200 isolates CDC587 and MN8, which contain the α-toxin pseudogene ( hla − ), MNPE ( hla + ), and MNPE isogenic hla knockout ( hla KO), were observed via LIVE/DEAD® staining and confocal microscopy. All TSS strains grew to similar bacterial densities (1–5 × 10 8  CFU) on the mucosa and were proinflammatory over 3 days. However, MNPE formed biofilms with significant reductions in the mucosal viability whereas neither CDC587 ( hla − ), MN8 ( hla − ), nor MNPE hla KO formed biofilms. The latter strains were also less cytotoxic than wild-type MNPE. The addition of exogenous, purified α-toxin to MNPE hla KO restored the biofilm phenotype. We speculate that α-toxin affects S. aureus phenotypic growth on vaginal mucosa by promoting tissue disruption and biofilm formation. Further, α-toxin mutants ( hla − ) are not benign colonizers, but rather form a different type of infection, which we have termed high density pathogenic variants (HDPV).
Microbiology biofilm alpha-toxin epithelium toxic shock syndrome Staphylococcus aureus vaginal mucosa

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