Actinobacillus muris sp. nov. isolated from mice.

Several unclassified strains were obtained during investigations of the aerobic pharyngeal flora of healthy white laboratory mice originating from four different colonies. Nineteen strains formed a group tentatively designated taxon 12. Comparative investigations including taxon 12, P. ureae sensu stricto. "P. urea" strain Ackerman 80-443D, P. pneumotropica sensu stricto, P. pneumotropica type Heyl, P. pneumotropica type Henriksen and "H. influenzae-murium" showed that taxon 12 was identical with "P. ureae" strain Ackerman 80-443D but different from P. ureae sensu stricto and other species belonging to the family Pasteurellaceae Pohl 1981. The G + C content of DNA from the suggested reference strain for taxon 12 was within the limits for Pasteurellaceae. DNA:DNA hybridizations linked taxon 12 to the genus Actinobacillus via the avian hemolytic Actinobacillus-like complex (27). The name Actinobacillus muris is proposed for taxon 12.