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Spxa1 Involved In Hydrogen Peroxide Production, Stress Tolerance And Endocarditis Virulence In Streptococcus Sanguinis, Lei Chen, Xiuchun Ge, Xiaojing Wang, Jenishkumar R. Patel, Ping Xu

Philips Institute for Oral Health Research Publications

Streptococcus sanguinis is one of the most common agents of infective endocarditis. Spx proteins are a group of global regulators that negatively or positively control global transcription initiation. In this study, we characterized the spxA1 gene in S. sanguinis SK36. The spxA1 null mutant displayed opaque colony morphology, reduced hydrogen peroxide (H2O2) production, and reduced antagonistic activity against Streptococcus mutans UA159 relative to the wild type strain. The ΔspxA1 mutant also demonstrated decreased tolerance to high temperature, acidic and oxidative stresses. Further analysis revealed that ΔspxA1 also exhibited a ~5-fold reduction in competitiveness in an animal model of …