title: 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.affiliation: Department of Pediatrics, Division of Infectious Diseases, School of Medicine, University of California at San Diego, La Jolla, California 92093-0687, USA. mhensler@ucsd.edu
authors.forename: Mary E
authors.initials: ME
authors.lastname: Hensler
authors.forename: George Y
authors.initials: GY
authors.lastname: Liu
authors.forename: Susan
authors.initials: S
authors.lastname: Sobczak
authors.forename: Kurt
authors.initials: K
authors.lastname: Benirschke
authors.forename: Victor
authors.initials: V
authors.lastname: Nizet
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Heldt
mesh_terms: D000367:Age Factors; D000375:Aging / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D003603:Cytotoxins / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D006460:Hemolysin Proteins / Q000235:genetics / Q000378:metabolism*; D008168:Lung / Q000382:microbiology / Q000473:pathology; D011014:Pneumonia / Q000382:microbiology* / Q000473:pathology; D011817:Rabbits; D012121:Respiration, Artificial; D013290:Streptococcal Infections / Q000382:microbiology* / Q000473:pathology; D013292:Streptococcus agalactiae / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics
chemical_list: D003603:Cytotoxins; D006460:Hemolysin Proteins