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The Electron Transport Chain Sensitizes Staphylococcus aureus and Enterococcus faecalis to the Oxidative Burst.
Painter, Kimberley L; Hall, Alex; Ha, Kam Pou; Edwards, Andrew M.
Afiliación
  • Painter KL; MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom.
  • Hall A; MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom.
  • Ha KP; MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom.
  • Edwards AM; MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom a.edwards@imperial.ac.uk.
Infect Immun ; 85(12)2017 12.
Article en En | MEDLINE | ID: mdl-28993457
ABSTRACT
Small-colony variants (SCVs) of Staphylococcus aureus typically lack a functional electron transport chain and cannot produce virulence factors such as leukocidins, hemolysins, or the antioxidant staphyloxanthin. Despite this, SCVs are associated with persistent infections of the bloodstream, bones, and prosthetic devices. The survival of SCVs in the host has been ascribed to intracellular residency, biofilm formation, and resistance to antibiotics. However, the ability of SCVs to resist host defenses is largely uncharacterized. To address this, we measured the survival of wild-type and SCV S. aureus in whole human blood, which contains high numbers of neutrophils, the key defense against staphylococcal infection. Despite the loss of leukocidin production and staphyloxanthin biosynthesis, SCVs defective for heme or menaquinone biosynthesis were significantly more resistant to the oxidative burst than wild-type bacteria in human blood or the presence of purified neutrophils. Supplementation of the culture medium of the heme-auxotrophic SCV with heme, but not iron, restored growth, hemolysin and staphyloxanthin production, and sensitivity to the oxidative burst. Since Enterococcus faecalis is a natural heme auxotroph and cause of bloodstream infection, we explored whether restoration of the electron transport chain in this organism also affected survival in blood. Incubation of E. faecalis with heme increased growth and restored catalase activity but resulted in decreased survival in human blood via increased sensitivity to the oxidative burst. Therefore, the lack of functional electron transport chains in SCV S. aureus and wild-type E. faecalis results in reduced growth rate but provides resistance to a key immune defense mechanism.
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Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Staphylococcus aureus / Estallido Respiratorio / Enterococcus faecalis / Superóxidos / Transporte de Electrón / Viabilidad Microbiana / Antibacterianos Límite: Humans Idioma: En Revista: Infect Immun Año: 2017 Tipo del documento: Article País de afiliación: Reino Unido

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Staphylococcus aureus / Estallido Respiratorio / Enterococcus faecalis / Superóxidos / Transporte de Electrón / Viabilidad Microbiana / Antibacterianos Límite: Humans Idioma: En Revista: Infect Immun Año: 2017 Tipo del documento: Article País de afiliación: Reino Unido