Prevotella is a genus of Gram-negative bacteria. Bacteroides melaninogenicus has been reclassified and split into Prevotella melaninogenica and Prevotella intermedia. Prevotella spp. are members of the oral and vaginal flora, and are recovered from anaerobic infections of the respiratory tract. These infections include aspiration pneumonia, lung abscess, pulmonary empyema, and chronic otitis media and sinusitis. They have been isolated from abscesses and burns in the vicinity of the mouth, bites, paronychia, urinary tract infection, brain abscesses, osteomyelitis, and bacteremia associated with upper respiratory tract infections. Prevotella spp. predominate in periodontal disease and periodontal abscesses.