Recovery and pathogenicity of several Salmonella species isolated from mice

Salmonella agona, S anatum, and S oranienburg were isolated from the feces of mice in the course of screening over 4,000 fecal samples from rodents in 22 research and production facilities. The rodents were monitored repeatedly over an 8-month period in 1979-80. These three Salmonella isolates were cultured from mice at 11 of the 22 facilities. Salmonella oranienburg was found in 56% (14 of 25) of Salmonella positive accessions, S anatum in 36% (nine of 25), S agona in 4% (one of 25), and both S oranienburg and S anatum were isolated in one accession. In order to determine the potential pathogenicity of these three Salmonella species, groups of DBA/2N mice were experimentally infected with the three agents. Several animals died acutely of apparent septicemia several days post-inoculation. Mice continued to shed the organisms in the feces for up to 5 weeks post-inoculation at which time they were necropsied and cultured extensively. Culture of visceral organs revealed mice to have systemic dissemination regardless of the Salmonella species. It was concluded that these three Salmonella species were regularly shed in the feces and, although not highly pathogenic, they had the potential to be invasive and cause disease when mice were stressed.