CAMP factor is not essential for systemic virulence of Group B Streptococcus

Microb Pathog. 2008 Jan;44(1):84-8. doi: 10.1016/j.micpath.2007.08.005. Epub 2007 Aug 14.

Abstract

The Gram-positive pathogen Group B Streptococcus (GBS) is the leading cause of bacterial pneumonia, sepsis, and meningitis in human newborns. GBS elaborates a pore-forming toxin known as CAMP factor that synergizes with Staphylococcus aureus beta-toxin, generating a co-hemolytic reaction useful in identification of GBS in the clinical laboratory. To evaluate the indirect evidence implicating CAMP factor in GBS pathogenesis, the cfb gene encoding the pore-forming cytotoxin was deleted by precise allelic replacement. The virulence properties of the CAMP factor mutant were then explored by a series of in vitro and in vivo assays. Compared to wild-type, the isogenic GBS Deltacfb mutant demonstrated equivalent phagocyte resistance and endothelial cell invasiveness and also retained full virulence in a mouse model of infection. Our data suggest that CAMP factor expressed in its native context is not essential for systemic virulence of GBS.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antimicrobial Cationic Peptides
  • Bacterial Proteins / physiology*
  • Cathelicidins
  • Genetic Complementation Test
  • Hemolysin Proteins / physiology*
  • Humans
  • Macrophages
  • Mice
  • Mice, Inbred C57BL
  • Mutagenesis, Site-Directed / methods
  • Mutation
  • Phenotype
  • Streptococcal Infections
  • Streptococcus agalactiae / genetics
  • Streptococcus agalactiae / pathogenicity*
  • Survival Analysis
  • Time Factors
  • Virulence / physiology*

Substances

  • Antimicrobial Cationic Peptides
  • Bacterial Proteins
  • CAMP protein, Streptococcus
  • Cathelicidins
  • Hemolysin Proteins
  • ropocamptide