The aerobic bacterial flora of laboratory rats from a danish breeding centre
The aerobic bacterial flora of barrier-maintained laboratory rats from 12 ditferent units was examined by the use of non-seleetive bacteriological cultivation. All rats were randomly sampled healthy rats. The number of infected clonies out of the
total number of examined colonies is given with the mean prevalence observed within the colonies for each of the bacterial species identified. The minimal sample size for detection of the organisms in routine microbiological] monitoring is estimated on basis 01' the prevalences observed. Bacterial species from the groups Micrococcaceae, Streptococcaceae, Lactobacillus spp, Bacillus spp, Corynebacterium spp. Enterobacteriaceae, Neisseriaceae, Pasteurellaceae and Pseudomanadaceae
were found. The most frequently isolated species was Staphylococcus aureus in the respiratory organs and Escericia coli in the intestines. The prevalence of the different bacterial species within the colonies varied from 3.1 to 69.3. The minimal sample size for each bacterial species varies from 3 to 95.