Bacteroidetes

Bacteroidetes
Scientific classification
Domain:	Bacteria
Phylum:	Bacteroidetes
Classes
Bifissio spartinae ♠ Xin & Zhou 2001 ‘Candidatus Amoebophilus’Horn et al. 2001 ‘Candidatus Cardinium’ Zchori-Fein et al. 2004 ‘Candidatus Paenicardinium’ Noel and Atibalentja 2006 Toxothrix ♪ Molisch 1925 Venteria ♠ Bae 2005 Bacteroidia Bacteroidales ‘Candidatus Armantifilum’ Desai et al. 2010 ‘Candidatus Azobacteroides’ ‘Candidatus Symbiothrix’ Hongoh et al. 2007 ‘Candidatus Vestibaculum’ Stingl et al. 2004 Sunxiuqinia Qu et al. 2011 Bacteroidaceae Pribram 1933 Marinilabiaceae Porphyromonadaceae Prevotellaceae Rikenellaceae Flavobacteria Cavalier-Smith 2002 Flavobacteriales Blattabacteriaceae Cryomorphaceae Bowman et al. 2003 Flavobacteriaceae Reichenbach et al. 1992 emend. Bernardet et al. 2002 Schleiferiaceae Albuquerque et al. 2011 Sphingobacteria Sphingobacteriales Chitinophagaceae Kämpfer et al. 2011 Cyclobacteriaceae Cytophagaceae Stanier 1940 Flammeovirgaceae Yoon et al. 2011 Rhodothermaceae Saprospiraceae Sphingobacteriaceae Steyn et al. 1998

The phylum Bacteroidetes is composed of three large classes of bacteria that are widely distributed in the environment, including in soil, in sediments, sea water and in the guts and on the skin of animals.

By far, the ones in the Bacteroidia class are the most well-studied, including the genus Bacteroides (an abundant organism in the feces of warm-blooded animals including humans), and Porphyromonas, a group of organisms inhabiting the human oral cavity. The class Bacteroidia was formally called Bacteroidetes as it was until recently the only class in the phylum, the name was changed in the fourth volume of Bergey's Manual of Systematic Bacteriology.

Members of the genus Bacteroides are opportunistic pathogens. Rarely are members of the other two classes pathogenic to humans.

Researcher Jeffrey Gordon and his colleagues found that obese humans and mice had intestinal flora (gut flora) with a lower percentage of Bacteroidetes and relatively more bacteria from the Firmicutes family. However, they are unsure if Bacteroidetes prevent obesity or if these intestinal flora are merely preferentially selected by intestinal conditions in those who are not obese.

This phylum is sometimes grouped with Chlorobi, Fibrobacteres, Gemmatimonadates, Caldithrix and Marine group A to form the FCB group or superphylum. In the alternative classification system proposed by Cavalier-Smith, this taxa is instead a class in the Sphingobacteria phylum.

Phylogeny

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI) and the phylogeny is based on 16S rRNA-based LTP release 106 by The All-Species Living Tree Project

?Bifissio spartinae ♠ Xin & Zhou 2001 ?‘Candidatus Amoebophilus asiaticus’Horn et al. 2001 ?‘Candidatus Cardinium hertigii’ Zchori-Fein et al. 2004 ?‘Candidatus Paenicardinium endonii’ Noel and Atibalentja 2006 ?Toxothrix trichogenes ♪ (Cholodny 1924) Beger 1953 ?Venteria marina ♠ Bae 2005 Rhodothermaceae Balneola-Gracilimonas clade Thermonema clade Flammeovirgaceae   Cytophagales Reichenbachiella Nedashkovskaya et al. 2005 emend. Cha et al. 2011 Flammeovirgaceae 2 [incl. Ekhidna lutea] Marivirga Nedashkovskaya et al. 2010 Cyclobacteriaceae [incl. Rhodonellum psychrophilum] Cytophagaceae Saprospiraceae Chitinophagaceae Sphingobacteriaceae   Flavobacterales ?'Candidatus Sulcia muelleri' Moran et al. 2005 ?'Candidatus Uzinura diaspidicola' Gruwell et al. 2007 ?Schleiferia thermophila Albuquerque et al. 2011 {Schleiferiaceae} ?Blattabacteriaceae Cryomorphaceae 2 Flavobacteriaceae Cryomorphaceae 1   Bacteroidales ?‘Candidatus Armantifilum devescovinae’ Desai et al. 2010 ?‘Candidatus Azobacteroides pseudotrichonymphae’ ?‘Candidatus Symbiothrix dinenymphae’ Hongoh et al. 2007 ?‘Candidatus Vestibaculum illigatum’ Stingl et al. 2004 ?Marinilabilia salmonicolor (Veldkamp 1961) Nakagawa and Yamasato 1996 emend. Suzuki et al. 1999 ?Sunxiuqinia elliptica Qu et al. 2011 Meniscus glaucopis Irgens 1977 Prolixibacter bellariavorans Holmes et al. 2007 Rikenellaceae Cytophaga fermentans Bachmann 1955 Marinifilum fragile Na et al. 2009 Alkaliflexus imshenetskii Zhilina et al. 2005 Anaerophaga thermohalophila Denger et al. 2002 Porphyromonadaceae 2 Porphyromonadaceae 3 Porphyromonadaceae 1 Porphyromonadaceae 4 Porphyromonadaceae 5 Bacteroidaceae [incl. Prevotellaceae]

Notes
♠ Strains found at the National Center for Biotechnology Information (NCBI) but not listed in the LPSN
♪ Prokaryotes where no pure (axenic) cultures are isolated or available, i. e. not cultivated or can not be sustained in culture for more than a few serial passages

External links

• Phylogenomics and Evolutionary Studies on Bacteriodetes, Chlorobi and Fibrobacteres Species Bacterial (Prokaryotic) Phylogeny Webpage