TAXONOMY: cellular organisms -> Bacteria -> Bacteroidetes/Chlorobi group -> Bacteroidetes -> Bacteroidia
The class 'Bacteroidia' is composed of a single order of environmental bacteria. By far, the Bacteroidales order are the most well- studied of the Bacteroidetes. Some members of the genus Bacteroides are opportunistic pathogens.Bergey's Manual of Systematic Bacteriology, 2nd ed., vol. 1 (The Archaea and the deeply branching and phototrophic Bacteria) (D.R. Boone and R.W. Castenholz, eds.), Springer-Verlag, New York (2001). pp. 465-466. Before the fourth volume ofBergey's Manual of Systematic Bacteriology came out, it was referred to as class Bacteroidetes.