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A Nonhemolytic Group B Streptococcus Strain Exhibits Hypervirulence.

ABSTRACT: Group B streptococci (GBS) are Gram-positive bacteria that are a leading cause of neonatal infections. Most invasive isolates are ?-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.

SUBMITTER: Gendrin C

PROVIDER: S-EPMC5853813 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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A Nonhemolytic Group B Streptococcus Strain Exhibits Hypervirulence.

Gendrin Claire C Vornhagen Jay J Armistead Blair B Singh Pallavi P Whidbey Christopher C Merillat Sean S Knupp David D Parker Robert R Rogers Lisa M LM Quach Phoenicia P Iyer Lakshminarayan M LM Aravind L L Manning Shannon D SD Aronoff David M DM Rajagopal Lakshmi L

The Journal of infectious diseases 20180301 6

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 kina ...[more]

PMID: 29244079

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