Gram-negative bacilli are responsible for numerous diseases. Some are commensal organisms present among normal intestinal flora. These commensal organisms plus others from animal or environmental reservoirs may cause disease. UTIs, diarrhea, peritonitis, and bloodstream infections are commonly caused by gram-negative bacilli. Plague, cholera, and typhoid fever are rare but serious gram-negative infections.

Last full review/revision August 2009 by Burke A. Cunha, MD