A Pasteurella pneumotropica Strain of Mouse Origin Colonizes Rats but is Out Competed by a P. pneumotropica Strain of Rat Origin

  • R Boot Laboratory for Infectious Diseases and Screening, National Institute of Public Health and the Environment


Mouse and rat Pasteurellaceae have been found to differ in phenotypic characteristics but both animal species  may be infected by each other’s bacterial strains. We explored the possibility that a mouse Pasteurella  strain colonizing rats would be out competed by a subsequent infection of a rat Pasteurella strain. 

Rats were dosed intranasally and orally with the mouse P. pneumotropica biotype Jawetz strain NCTC  8141T and exposed to pen-mates infected with the rat P. pneumotropica biotype Heyl strain SSI P331 by  co-housing. 

Rats were tested by PCR using primer sets developed for the specific detection of each biotype respectively. 

The co-housing and exposure of rats initially infected by the mouse P. pneumotropica with pen-mates harbouring  the rat P. pneumotropica led to disappearance of the mouse bacterium from the rats.  Our results question the suitability of Pasteurellaceae from contemporary laboratory animals to elucidate  associations between bacterial properties and host species.