A Nonhemolytic Group B Streptococcus Strain Exhibits Hypervirulence. (13th December 2017)

• Record Type: Journal Article
• Authors: Gendrin, Claire; Vornhagen, Jay; Armistead, Blair; Singh, Pallavi; Whidbey, Christopher; Merillat, Sean; Knupp, David; Parker, Robert; Rogers, Lisa M; Quach, Phoenicia; Iyer, Lakshminarayan M; Aravind, L; Manning, Shannon D; Aronoff, David M; Rajagopal, Lakshmi
• Is Part Of: Journal of infectious diseases. Volume 217:Number 6(2018)
• Page Start: 983
• Page End: 987
• Publication Date: 2017-12-13
• Subjects: hemolysis -- hyaluronidase -- nonhemolytic -- pigment -- Streptococcus agalactiae; Communicable diseases -- Periodicals; Diseases -- Causes and theories of causation -- Periodicals; Medicine -- Periodicals; Communicable Diseases -- Periodicals; Electronic journals; 616.9
• DOI: 10.1093/infdis/jix646
• Languages: English
• ISSNs: 0022-1899

Abstract

Abstract : A nonhemolytic and nonpigmented group B streptococcus clinical isolate exhibits hypervirulence and has a CovS mutation that confers constitutive kinase signaling. Abstract: Group B streptococci (GBS) are Gram-positive bacteria that are a leading cause of neonatal infections. Most invasive isolates are β-hemolytic, and hemolytic activity is critical for GBS virulence. Although nonhemolytic GBS strains are occasionally isolated, they are often thought to be virulence attenuated. In this study, we show that a nonhemolytic GBS strain (GB37) isolated from a septic neonate exhibits hypervirulence. Substitution of tryptophan to leucine (W297L) in the sensor histidine kinase CovS results in constitutive kinase signaling, leading to decreased hemolysis and increased activity of the GBS hyaluronidase, HylB. These results describe how nonpigmented and nonhemolytic GBS strains can exhibit hypervirulence.