Transfer of Bifidobacterium inopinatum and Bifidobacterium denticolens to Scardovia inopinata gen. nov., comb. nov., and Parascardovia denticolens gen. nov., comb. nov., respectively.

Bifidobacterium inopinatum Crociani et al. 1996 and Bifidobacterium denticolens Crociani et al. 1996 have distinct phenotypic characteristics and low G+C contents compared with other bifidobacteria. In the 16S rRNA phylogenetic tree, these two species grouped in an independent subcluster. In our previous work, partial heat-shock protein 60 (HSP60) gene-sequence analysis also indicated that these two species had distinct taxonomic positions. In this work, the complete HSP60 genes of five representative bacterial strains were sequenced by using an inverse PCR method. The complete sequence similarities turned out to be at the same level as those of the partial genes, thus confirming the result based on partial sequence analysis. On the basis of all the evidence mentioned above, it is proposed that these two species should be transferred to two new genera as Scardovia inopinata gen. nov., comb. nov., and Parascardovia denticolens gen. nov., comb. nov.