[3] According to the 16S rRNA-based LTP release 106 published by 'The All-Species Living Tree' Project, the order Bifidobacteriales is a clade nested within the suborder Micrococcineae, also the genus Bifidobacterium is paraphyletic to the other genera within the family, i.e. the other genera are nested within Bifidobacterium.

Comparative analysis of aligned protein sequences has led to the discovery of two conserved signature indels which are specific for the order Bifidobacteriales.

The second indel that has been identified is a 1 amino acid insertion in glucose-6-phosphate dehydrogenase found in all Bifidobacterium species and G. vaginalis, but not in any other Actinomycetota.

This indel is thus characteristic of the clade consisting of Bifidobacterium species and G. vaginalis and can be used to distinguish these genera from the rest of the order Bifidobacteriales.

[4] The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN).