Salmonellosis is one of the important diseases in laboratory animals.
The present study was conducted to establish the assay of salmonella infections in mice. Eight-sig conventional mice randomly collected from 8 breeders and 15 specific pathogen free mice from Veterinary Research Institute in Korea were examined for detection of salmonellae during the period of April 1986 to March 1987.
The results obtained were summarized as follows:
1. Salmonellae were isolated from 24(27.9%) of 86 conventional mice, while no salmonellae were isolated from 15 specific pathogen free mice. Of 86 conventional mice, 18(20.9%)were isolated (salmonellae) in small intestine, 14(16.3%) in large intestine and 16(18.6%) in liver, respectively.
2. Comparing the efficiency of Salmonella-Shigella(SS), Xylose Lysine Deoxycholate(XLD) and MacConkey agar for the detection of salmonellae, XLD agar was the best medium for isolation of salmonellae from the intestine samples of mice.
The isolation rates of salmonellae in small and large intestine on the XLD agar were 94.4% and 85.7%, but on the SS agar were 50.0% and 57.1%, and on the MacConkey agar were 44.4% and 57.1% respectively.
In 16 cases of liver, isolation rates of Salmonellae on SS, XLD and MacConkey agar were 100%, 75.0% and 81.3%, respectively.
Therefore, SS agar was more efficient than XLD and MacConkey agar for isolation of Salinonellae from liver samples of mice.
3. Salmonellae isolated from 24 mice were 51 strains, which were identified as Salmonella enteritiudis by means of biochemical and serological tests. This fact found that murine salmonellosis in Korea was predominantly caused by S. enteritidis.
4. On necropsy of 24 mice infected with Salmonellae, the spleen was enlarged to 2 to 4 times than its normal size, The liver showed congestion, scattered necrotic foci of various sizes, friability in consistency and variation of color from deep red to brownish yellow.
The intestine showed moderate to severe catarrhal inflammation, congestion and hemorrhage of the mucosa.
However, no lesions were found in SPF mice.
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