First isolated from fecal specimen in 1933, type strain Parabacteroides distasonis was originally classified under the name Bacteroides distasonis.[6] The strain was re-classified to form the new genus Parabacteroides in 2006.[7]Parabacteroides currently comprise 21 phylogenetically, ecologically, and metabolically diverse species, 11 of which are validly published in the taxonomic database
List of Prokaryotic names with Standing in Nomenclature (LPSN).[2]
Within the Parabacteroides genus, species P. distasonis and
P. goldsteinii have been associated with beneficial effects in human health, relating to their integral role in
gut microbiota along the digestive tract.[8][9][10]
Taxonomy
The
taxon ID number used for prokaryotic genus Parabacteroides is 516255.[2] Parent taxon comes from bacterial family Tannerellaceae, identified by number 29533 in the online
LPSN database.[2]
Genomics
The genomes of Parabacteroides are highly variable, both across species and within a single strain. For example, genomes isolated from type strain P. distasonis range in size from approximately 4.5 to 5.2 Mb (
megabases) and encode over 2,000 functional
proteins, signifying substantial variation within the species.[11]
Part of the bacterial order Bacteroidales present in the
human gut,Parabacteroides are commonly found within the gut microenvironment. Parabacteroides species constitute a significant component of
microbiota along the
digestive tract, benefitting from a
commensal relationship with the human body. Intestinal microbiota also benefit the human
host, modulating essential metabolism-related processes within the gut microenvironment.[12]
P. distasonis and
P. goldsteinii in particular form
biofilms in the
gut microbiota, allowing these species to survive under harsh conditions and maintain ample populations in extreme pH environments.[8] Recent studies elucidate new applications of Parabacteroides as
probiotics, supporting balanced microbiota composition as a benefit to human digestive health.[8] Both P. distasonis and P. goldsteinii exhibit anti-obesity effects via production of secondary
bile acids and
succinate within the gut microenvironment.[8][10] Studies on Parabacteroides species P. distasonis reveal metabolic benefits of this mechanism, including control of weight gain, decrease in
hyperglycemia, and amelioration of
hepatic steatosis and other metabolic diseases. [9]