Colonisation of rabbits with Staphylococcus aureus after experimental infection with high and low virulence strains

Four groups of 12 rabbits each were inoculated in the nose with strains with suspected differences in virulence. In the two groups infected with strains from severe outbreaks, belonging to a rabbit-pathogenic biotype-phage type combination, 6-12 rabbits were found positive at the successive bacteriological samplings over a period of 28 days. In the two other groups, infected with strains obtained from rabbitries without a history of staphylococcosis, the number of Staphylococcus aureus positive animals quickly became negative but increased again after 1 week to 1-5 positive animals until the end of the experiment. Two rabbits in each group inoculated with a high virulence strain developed purulent skin lesions, while in the groups inoculated with low virulence strains, all animals remained clinically healthy. Results indicate that colonisation capacity is an important virulence determinant in rabbit staphylococcosis.