A non-hemolytic 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. While non-hemolytic GBS strains are occasionally isolated, they are often thought to be virulence attenuated. Here, we show that a non-hemolytic 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 non-pigmented and non-hemolytic GBS strains can exhibit hypervirulence.

from # All Medicine by Alexandros G. Sfakianakis via alkiviadis.1961 on Inoreader http://ift.tt/2BkpcMe