Pyruvate oxidase of Streptococcus pneumoniae contributes to pneumolysin release

BMC Microbiology

Research Article

Keun S. Seo¹  Lindsey R. Brown²  Ridge C. Dabbs²  Joseph C. Bryant²  Katie L. Oswalt²  Justin A. Thornton²  Janet R. Donaldson³  Jason W. Rosch⁴  Larry S. McDaniel⁵ 

[1] Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA;Department of Biological Sciences, Mississippi State University, 295 E Lee Blvd., Harned Hall, Rm 219, 39762, Mississippi State, MS, USA;Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, USA;Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, TN, USA;Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, USA;

关键词: Streptococcus pneumoniae;    Pneumococcus;    Pneumolysin;    Virulence;    Toxin;    Metabolism;    Protein secretion;    Cytotoxicity;   

DOI  :  10.1186/s12866-016-0881-6

 received in 2016-06-08, accepted in 2016-10-28,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundStreptococcus pneumoniae is one of the leading causes of community acquired pneumonia and acute otitis media. Certain aspects of S. pneumoniae’s virulence are dependent upon expression and release of the protein toxin pneumolysin (PLY) and upon the activity of the peroxide-producing enzyme, pyruvate oxidase (SpxB). We investigated the possible synergy of these two proteins and identified that release of PLY is enhanced by expression of SpxB prior to stationary phase growth.ResultsMutants lacking the spxB gene were defective in PLY release and complementation of spxB restored PLY release. This was demonstrated by cytotoxic effects of sterile filtered supernatants upon epithelial cells and red blood cells. Additionally, peroxide production appeared to contribute to the mechanism of PLY release since a significant correlation was found between peroxide production and PLY release among a panel of clinical isolates. Exogenous addition of H2O2 failed to induce PLY release and catalase supplementation prevented PLY release in some strains, indicating peroxide may exert its effect intracellularly or in a strain-dependent manner. SpxB expression did not trigger bacterial cell death or LytA-dependent autolysis, but did predispose cells to deoxycholate lysis.ConclusionsHere we demonstrate a novel link between spxB expression and PLY release. These findings link liberation of PLY toxin to oxygen availability and pneumococcal metabolism.

【 授权许可】

CC BY   
© The Author(s). 2016