Abstract
Mice and rats were experimentally infected with Pasteurellaceae isolated from mice, rats, hamsters and gerbils. Mice and rats were most heavily colonized by strains originally isolated from mice and rats respectively, and to a lesser extent by Pasteurellaceae from hamsters and gerbils. Colonization was generally accompanied by seroconversion. Gross pathology of the lungs was not observed. We conclude that Pasteurellaceae-free SPF mice and rats can be colonized by members of this bacterial family present in other rodent species.