Newborn sepsis following antepartum group B streptococcal maternal infection in rats

Group B streptococcus is an important pathogen in man and infection due to this bacteria is responsible for significant mortality and morbidity in neonates. An animal model of neonatal infection caused by group B streptococcus that results from vertical transmission is described. Nine pregnant Sprague-Dawley rats received intraperitoneal inoculation of 10(9)-10(10) colony forming units of group B streptococcus on day 20 or 21 of gestation. Four of nine rats died following inoculation. A total of 51 pups was born to the surviving five mothers. Pups were sacrificed at 4- to 8-h intervals and cultures of blood, brain, liver, and spleen were obtained. Nineteen of 51 pups (37%) had group B streptococcus isolated from blood or tissues within the first 48 h of life. Results suggest that antepartum systemic infection in rats can result in vertical transmission of disease. This animal model can be used to further study the mechanisms of transmission of group B streptococcus and the pathogenesis and treatment of neonatal sepsis caused by this pathogen.