Bifidobacteriaceae

Bi.fi.do.bac.te.ri.a’ce.ae. N.L. neut. n. Bifidobacterium, type genus of the family; L. fem. pl. n. suff. -aceae, ending to denote a family; N.L. fem. pl. n. Bifidobacteriaceae, the Bifidobacterium family. The family Bifidobacteriaceae is defined by phylogenetic criteria supported by biochemical features, notably, its degradation of glucose by the fructose 6-phosphate shunt in which fructose-6-phosphoketolase activity is the key enzyme. It consists of several genera, including Bifidobacterium (with the most species), Alloscardovia, Aeriscardovia, Bombiscardovia, Galliscardovia, Gardnerella, Neoscardovia, Parascardovia, Pseudoscardovia, and Scardovia. The newly described Candidatus Ancillula is a deep-branching sister group of this family, sharing phosphoketolase genes but positioned externally in phylogenetic trees based on 16S rRNA and genomic sequences. Members of this family are pleomorphic, nonmotile, nonspore-forming, and nonfilamentous rods, usually Gram-stain-positive, except Gardnerella, which is Gram-stain-variable. They are primarily anaerobic, though some species tolerate oxygen in the presence of CO2 or grow aerobically. They are chemoorganotrophs with fermentative metabolism, producing acid from carbohydrates, mainly acetic and lactic acid, without gas formation. Their DNA G+C content ranges from Updated based on the original article Bruno Biavati. 42 to 67 mol%, and their optimal growth temperature is 30–39∘C. Bifidobacteriaceae species have been isolated from animals, humans, and traditional fermented foods. Most are nonpathogenic, but Bifidobacterium dentium, Scardovia inopinata, and Parascardovia denticolens are associated with dental caries, while Gardnerella species can cause bacterial vaginosis and urogenital infections. DNA G + C content (mol%): 42–67 (genome). Type genus: Bifidobacterium Orla-Jensen 1924AL.