Virulence role of group B Streptococcus beta-hemolysin/cytolysin in a neonatal rabbit model of early-onset pulmonary infection

J Infect Dis. 2005 Apr 15;191(8):1287-91. doi: 10.1086/428946. Epub 2005 Mar 10.


We examined the virulence role of group B Streptococcus (GBS) beta-hemolysin/cytolysin (beta h/c) in a neonatal-rabbit model of GBS pulmonary infection. Rabbits infected intratracheally with wild-type (wt) GBS developed focal pneumonia and, by 18 h after infection, had 100-fold more bacteria in lung tissue than did rabbits infected with a delta beta h/c mutant. Mortality (40% vs. 0%), development of bacteremia, and mean bacterial blood counts were all significantly higher in the rabbits challenged with wt GBS than in those challenged with the delta beta h/c mutant. Lung compliance during mechanical ventilation was impaired after injection of wt GBS but not after injection of the Delta beta h/c mutant strain. This work, to our knowledge, provides the first in vivo evidence for a critical role of the beta h/c toxin in GBS neonatal pneumonia and in the breakdown of the pulmonary barrier to systemic infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Aging / physiology*
  • Animals
  • Animals, Newborn
  • Cytotoxins / genetics
  • Cytotoxins / metabolism*
  • Disease Models, Animal*
  • Hemolysin Proteins / genetics
  • Hemolysin Proteins / metabolism*
  • Lung / microbiology
  • Lung / pathology
  • Pneumonia / microbiology*
  • Pneumonia / pathology
  • Rabbits
  • Respiration, Artificial
  • Streptococcal Infections / microbiology*
  • Streptococcal Infections / pathology
  • Streptococcus agalactiae / genetics
  • Streptococcus agalactiae / metabolism
  • Streptococcus agalactiae / pathogenicity*
  • Virulence / genetics


  • Cytotoxins
  • Hemolysin Proteins