A pleomorphic, Gram-stain-negative, rod-shaped, indole-, oxidase- and catalase-negative,
non-spore-forming, non-motile bacterium (strain 131000547T) was isolated from the lungs of a
cat with pneumonia. On the basis of 16S rRNA gene sequence analyses the strain was
assigned to the genus Streptobacillus with 97.6 % sequence similarity to the type strain of
Streptobacillus moniliformis and 94.6 % to that of Streptobacillus hongkongensis. The clear
differentiation of strain 131000547T from Streptobacillus moniliformis and Streptobacillus
hongkongensis was also supported by gyrB, groEL, and recA nucleotide and amino acid
sequence analysis. DNA–DNA hybridization demonstrated #19.9 % (reciprocal 28.7 %)
DNA–DNA relatedness between strain 131000547T and Streptobacillus moniliformis DSM
12112T. Physiological data confirmed the allocation of strain 131000547T to the family
Leptotrichiaceae. Strain 131000547T has a unique profile of enzyme activities allowing
differentiation from the most closely related species. Within the genus Streptobacillus, isolate
131000547T could also unambiguously be separated from Streptobacillus moniliformis and
Streptobacillus hongkongensis by both matrix-assisted laser desorption ionization time-of-flight
mass spectrometry and Fourier transform-infrared spectroscopy. On the basis of these data, a
novel species of the genus Streptobacillus, Streptobacillus felis sp. nov., is proposed with the
type strain 131000547T (5DSM 29248T5CCUG 66203T5CCM 8542T). Emended
descriptions of the genus Streptobacillus and of Streptobacillus moniliformis are also given.