Clostridium difficile: Old and new observations

Clostridium difficile is now the most frequent bacterial enteric pathogen in the developed world. This organism has been the recognized agent of 20% to 25% of cases of antibiotic-associated diarrhea since its discovery in 1978. Like enteric pathogens, it causes a wide range of clinical disease ranging from asymptomatic colonization or trivial diarrhea at one end of the spectrum and life threatening pseudomembranous colitis at the other. Effective methods to diagnose this condition with toxin assays and treatment with either vancomycin or metronidazole have been in widespread use for 25 years. During the past 3 to 4 years there has been the recognition of a new strain designated the NAP-1 strain which has been associated with some unique features including epidemics in geographically defined areas, more serious forms of disease and relatively refractoriness to standard therapy. This NAP-1 strain is now found rather frequently in Canada, the United States, and much of Europe. This paper will review much of the current knowledge of C. difficile, current methods of recognition and management, and implication of the newly recognized epidemic strain.