Open AccessA Nonhemolytic Group B Streptococcus Strain Exhibits Hypervirulence
Author(s) -
Claire Gendrin,
Jay Vornhagen,
Blair Armistead,
Pallavi Singh,
Christopher Whidbey,
Sean Merillat,
David Knupp,
Robert E. Parker,
Lisa M. Rogers,
Phoenicia Quach,
Lakshminarayan M. Iyer,
L. Aravind,
Shan D. Manning,
David M. Aronoff,
Lakshmi Rajagopal
Publication year - 2017
Publication title -
the journal of infectious diseases
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 2.69
H-Index - 252
eISSN - 1537-6613
pISSN - 0022-1899
DOI - 10.1093/infdis/jix646
Subject(s) - virulence , streptococcus agalactiae , microbiology and biotechnology , hemolysis , streptococcus , group b , strain (injury) , group a , biology , bacteria , haemolysis , medicine , immunology , gene , biochemistry , genetics , anatomy
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.
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