Bifidobacterium globosum, Subjective Synonym of Bifidobacterium pseudolongum, and Description of Bifidobacterium pseudolongum subsp. pseudolongum comb. nov. and Bifidobacterium pseudolongum subsp. globosum comb. nov.

Summary Nineteen strains of Bifidobacterium pseudolongum and Bifidobacterium globosum isolated from various animals were studied with respect to their DNA base compositions, DNA similarities and phenotypic characteristics. These strains were divided into four groups. Three strains (B. pseudolongum) exhibited 88–93% similarity with the type strain of B. pseudolongum and 63–65% similarity with the type strain of B. globosum . Eight strains (B. globosum) were related 89 to 96% to the type strain of B. globosum and 57 to 66% to the type strain of B. pseudolongum . The other eight strains (Intermediate groups I and II) showed moderate DNA similarity values of 54–75% as compared to the two type strain, and two strains (Intermediate group I) were identical. The G+C contents of all strains exceeded 63.0 mol% and the average G+C contents of DNAs from B. pseudolongum, B. globosum , Intermediate groups I and II were 64.8, 64.1, 63.3 and 65.3 mol%, respectively. B. pseudolongum and B. globosum showed similar properties in carbohydrate fermentation patterns and electrophoretic mobility of 6-phosphogluconate dehydrogenase, whereas they differed in their ability to grow in 4.5% sodium malate at 30 °C. The strains of Intermediate group I differed from other groups in these properties. Our results indicate that B. globosum is genetically and phenotypically very similar to B. pseudolongum . Therefore we propose to consider these two species as subspecies: B. pseudolongum subsp. pseudolongum and B. pseudolongum subsp. globosum .