Reference Work Entry

The Prokaryotes

pp 381-427

The Medically Important Bacteroides spp. in Health and Disease

  • C. Jeffrey Smith
  • , Edson R. Rocha
  • , Bruce J. Paster

Introduction to the Bacteroides

The genus Bacteroides contains Gram-negative, nonsporeforming, nonmotile, anaerobic rods generally isolated from the gastrointestinal tract (GI-tract) of humans and animals. Up until about 12 years ago the genus was quite diverse and included nearly every organism that fit this generalized description. In 1989, however, the genus was formally restricted to include only those organisms that are closely related to the type species, Bacteroides fragilis, resulting in a group that is much more biochemically and genetically cohesive (Shah and Collins, 1989). This group is now comprised of what were previously B. fragilis subspecies plus a few additional newly recognized species. The genus includes Bacteroides fragilis, B. thetaiotaomicron, B. ovatus, B. uniformis, B. vulgatus, B. distasonis, B. eggerthii, B. caccae, B. merdae and B. stercoris (Shah and Collins, 1989).

This narrowed description of the Bacteroides has resulted in a ...

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