Open Access Highly Accessed Open Badges Original research

Development of a model of focal pneumococcal pneumonia in young rats

Richard Malley12*, Anne M Stack1, Robert N Husson2, Claudette M Thompson3, Gary R Fleisher1 and Richard A Saladino14

Author Affiliations

1 Division of Emergency Medicine, Children's Hospital, Harvard Medical School, Boston MA, USA

2 Division of Infectious Diseases, Children's Hospital, Harvard Medical School, Boston MA, USA

3 Harvard School of Public Health, Boston MA, USA

4 Division of Pediatric Emergency Medicine, Department of Pediatrics, Children's Hospital, Pittsburgh PA, USA

For all author emails, please log on.

Journal of Immune Based Therapies and Vaccines 2004, 2:2  doi:10.1186/1476-8518-2-2

Published: 23 January 2004



A recently licensed pneumococcal conjugate vaccine has been shown to be highly effective in the prevention of bacteremia in immunized children but the degree of protection against pneumonia has been difficult to determine.


We sought to develop a model of Streptococcus pneumoniae pneumonia in Sprague-Dawley rats. We challenged three-week old Sprague-Dawley pups via intrapulmonary injection of S. pneumoniae serotypes 3 and 6B. Outcomes included bacteremia, mortality as well histologic sections of the lungs.


Pneumonia was reliably produced in animals receiving either 10 or 100 cfu of type 3 pneumococci, with 30% and 50% mortality respectively. Similarly, with type 6B, the likelihood of pneumonia increased with the inoculum, as did the mortality rate. Prophylactic administration of a preparation of high-titered anticapsular antibody prevented the development of type 3 pneumonia and death.


We propose that this model may be useful for the evaluation of vaccines for the prevention of pneumococcal pneumonia.