1. A Nonhemolytic Group B Streptococcus Strain Exhibits Hypervirulence
- Author
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Lisa M. Rogers, Blair Armistead, Robert E. Parker, Lakshmi Rajagopal, Sean Merillat, Claire Gendrin, Shannon D. Manning, David Knupp, Lakshminarayan M. Iyer, Phoenicia Quach, Christopher Whidbey, Pallavi Singh, L. Aravind, Jay Vornhagen, and David M. Aronoff
- Subjects
0301 basic medicine ,Histidine Kinase ,Hyaluronoglucosaminidase ,Virulence ,Biology ,medicine.disease_cause ,Group B ,Streptococcus agalactiae ,Microbiology ,Mice ,Major Articles and Brief Reports ,03 medical and health sciences ,Bacterial Proteins ,Leucine ,Hyaluronidase ,Streptococcal Infections ,medicine ,Animals ,Humans ,Immunology and Allergy ,reproductive and urinary physiology ,Strain (chemistry) ,Streptococcus ,Infant, Newborn ,Tryptophan ,bacterial infections and mycoses ,medicine.disease ,biology.organism_classification ,Hemolysis ,030104 developmental biology ,Infectious Diseases ,Amino Acid Substitution ,bacteria ,Bacteria ,medicine.drug - 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.
- Published
- 2017