ABSTRACT
Clostridium difficile is a gram-positive, anaerobic, spore-forming bacillus whose pathogenicity in the human gastrointestinal tract has paralleled advances in antimicrobial therapy. Prior to the age of antibiotics, C. difficile grew undisturbed in colonic mucosa, causing little damage or human disease. With the discovery of C. difficile as the causative agent for antibiotic-associated colitis, there has been a remarkable resurrection of this organism as pathogen, with intense scientific investigations examining epidemiology, pathophysiology, and effective clinical treatments that were developed within a few years of its rediscovery. Nosocomial outbreaks provided further opportunities for epidemiological study, and advances in molecular biology have resulted in cloning and sequencing of C. difficile toxins, prompting examination of cellular mechanisms of action. Despite the explosion of knowledge about the organism and associated disease, many questions remain. Areas for further study include effective methods of prevention, optimal treatment of recurrent disease, the role of host immune system factors, and possible prophylaxis with vaccine.
