A rat model for dose–response relationships of Salmonella Enteritidis infection

Authors

  • A.H. Havelaar,

    1. Microbiological Laboratory for Health Protection, National Institute of Public Health and the Environment, Bilthoven, the Netherlands
    Search for more papers by this author
  • J. Garssen,

    1. Laboratory for Pathology and Immunobiology, National Institute of Public Health and the Environment, Bilthoven, the Netherlands
    Search for more papers by this author
  • K. Takumi,

    1. Microbiological Laboratory for Health Protection, National Institute of Public Health and the Environment, Bilthoven, the Netherlands
    Search for more papers by this author
  • M.A. Koedam,

    1. Laboratory for Pathology and Immunobiology, National Institute of Public Health and the Environment, Bilthoven, the Netherlands
    Search for more papers by this author
  • J.B. Dufrenne,

    1. Microbiological Laboratory for Health Protection, National Institute of Public Health and the Environment, Bilthoven, the Netherlands
    Search for more papers by this author
  • F.M. Van Leusden,

    1. Microbiological Laboratory for Health Protection, National Institute of Public Health and the Environment, Bilthoven, the Netherlands
    Search for more papers by this author
  • L. De La Fonteyne,

    1. Laboratory for Pathology and Immunobiology, National Institute of Public Health and the Environment, Bilthoven, the Netherlands
    Search for more papers by this author
  • J.T. Bousema,

    1. Laboratory for Pathology and Immunobiology, National Institute of Public Health and the Environment, Bilthoven, the Netherlands
    2. Biomedical Health Sciences, Catholic University, Nijmegen, the Netherlands
    Search for more papers by this author
  • J.G. Vos

    1. Laboratory for Pathology and Immunobiology, National Institute of Public Health and the Environment, Bilthoven, the Netherlands
    Search for more papers by this author

Havelaar Microbiological Laboratory for Health Protection, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, the Netherlands.

Abstract

Aims: To develop an animal model to study dose–response relationships of enteropathogenic bacteria.

Methods and Results: Adult, male Wistar Unilever rats were exposed orally to different doses of Salmonella enterica serovar Enteritidis after overnight starvation and neutralization of gastric acid by sodium bicarbonate. The spleen was the most sensitive and reproducible organ for detection of dose-dependent systemic infection. Illness was only observed in animals exposed to doses of 108 cfu or more. At lower doses, histopathological changes in the gastro-intestinal tract were observed, but these were not accompanied by illness. Marked changes in numbers and types of white blood cells, as well as delayed-type hyperresponsiveness, indicated a strong, dose-dependent cellular immune response to Salm. Enteritidis.

Conclusions: The rat model is a sensitive and reproducible tool for studying the effects of oral exposure to Salm. Enteritidis over a wide dose range.

Significance and Impact of the Study: The rat model allows controlled quantification of different factors related to the host, pathogen and food matrix on initial stages of infection by food-borne bacterial pathogens.

Ancillary