Abstract
Twenty-two strains of bifidobacteria from the feces of chickens, rats, and rabbits, and from sewage, formed a single deoxyribonucleic acid (DNA) homology group displaying complete homology with Bifidobacterium longum subsp. animalis Mitsuoka biotype a strain R 101-8 (=ATCC 25527). The DNA relatedness of this group of strains to the known species of the genus Bifidobacterium ranged from 5 to 40%. Therefore, we propose that B. longum Reuter subsp. animalis Mitsuoka biotype a should be elevated to species rank as Bifidobacterium animalis (Mitsuoka) comb. nov. The type strain is ATCC 25527. Also, a small number of strains isolated from sewage are suggested as probably being distinctive bifidobacteria and are placed in two new groups designated “minimum” and “subtile” The reference strains for these groups are F392 (=ATCC 27538) and F395 (=ATCC 27537), respectively.