Deoxyribonucleic Acid Hybridization among Strains of Fusobacteria Isolated from Soft Tissue Infections of Cats: Comparison with Human and Animal Type Strains from Oral and Other Sites

Abstract

Fifty-two strains of Fusobacterium species were isolated from oral cavities or lesions contaminated with feline oral flora from 49 different cats. Forty-five strains were from purulent lesions, while the remaining seven strains came from the normal gingivae of three cats less than 6 months old. Of 36 strains which were phenotypically like Fusobacterium russii, 29 showed an average level of deoxyribonucleic acid (DNA) homology of 87% with the type strain of F. russii, strain ATCC 25533 (isolated from a cat). The remaining seven strains showed an average level of DNA relatedness to F. russii of 53%. An additional eight strains, which were identified as Fusobacterium necrophorum by biochemical tests, had polyacrylantide gel electrophoresis patterns unlike those of F. necrophorum and an average level of DNA homology with F. necrophorum ATCC 25286T(T = type strain) of 25%. These strains showed an average level of DNA homology with Fusobacterium alocis ATCC 35896Tof 96%, although the results of polyacrylamide gel electrophoresis and biochemical tests obtained with the isolated strains were unlike the results obtained with F. alocis ATCC 35896T. Four strains isolated from cats had biochemical characteristics of Fusobacterium nucleatum ATCC 25586T. The average level of intragroup DNA homology of these strains with F. nucleatum ATCC 25586Twas 66%, although their polyacrylamide gel electrophoresis patterns differed somewhat from those of the type strain. Four strains isolated from cats were identified as Fusobacterium naviforme on the basis of phenotypic tests; they had an average level of homology with the type strain of F. naviforme, strain ATCC 25832, of 17% and showed low degrees of relatedness with DNAs from all other type strains tested.