| Noun | 1. | Bacteroides - type genus of Bacteroidaceae; genus of Gram-negative rodlike anaerobic bacteria producing no endospores and no pigment and living in the gut of man and animalsbacteria genus - a genus of bacteria Bacteroidaceae, family Bacteroidaceae - family of bacteria living usually in the alimentary canal or on mucous surfaces of warm-blooded animals; sometimes associated with acute infective processes |