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

Abstract

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.

• Authors: Mary E Hensler, George Y Liu, Susan Sobczak, Kurt Benirschke, Victor Nizet, Gregory P Heldt
• Journal: The Journal of infectious diseases (J Infect Dis) Vol. 191 Issue 8 Pg. 1287-91 (Apr 15 2005) ISSN: 0022-1899 [Print] United States
• PMID: 15776375 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Cytotoxins
• Hemolysin Proteins

Topics

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