Group B streptococci (GBS) are the most common cause of sepsis and pneumonia in newborns. One effective antibacterial strategy in immunodeficient hosts is phagocytosis, but how virulent Gram-positive bacteria evade phagocytosis has been unclear. In the January 1 Journal of Clinical Investigation, Theresa O. Harris and colleagues at the University of Washington, Seattle, USA, show that a novel streptococcal surface protease promotes virulence, resistance to opsonophagocytosis, and cleavage of human fibrinogen (Journal of Clinical Investigation, 111:61-70, January 1, 2003).

Harris et al. screened numerous GBSs and isolated the cspA gene from a highly virulent strain. They observed that cspA encoded a surface-localized protein that promoted GBS survival through evasion of opsonophagocytosis. The cspA sequence indicated that it is a subtilisin-like extracellular serine protease, homologous to the streptococcal C5a peptidases and caseinases of lactic acid bacteria. In addition, they showed that cspA was required for GBS cleavage...

Interested in reading more?

Become a Member of

Receive full access to more than 35 years of archives, as well as TS Digest, digital editions of The Scientist, feature stories, and much more!
Already a member?