Pathophysiology, diagnosis and treatment of Clostridium difficile infection.

Clostridium difficile infection has become in recent years an important nosocomial threat. Prevention of the spread of C. difficile infection among long term hospitalized patients is a major challenge since C. difficile spores can persist indefinitely in the hospital environment. Following antibiotic therapy that disrupts the normal bacterial flora of the colon, C. difficile can colonize the large intestine. The bacteria releases two large protein toxins that bind to colonocytes and mediate an acute inflammatory diarrhea characterized by an abundant exudate rich in neutrophils and proteins that in some cases can form the typical "pseudomembrane". C. difficile infection shows a spectrum of severity from asymptomatic carrier to fulminant acute pseudomembraneous colitis. The gold standard for the laboratory diagnosis of C. difficile infection is the stool-cytotoxin test, however recently developed immunoassays represent a good alternative. The treatment of C. difficile infection is based on the severity of the clinical picture. In patients with mild diarrhea discontinuation of the causing antibiotic can be an adequate therapeutic approach, whereas patients with more severe symptoms require antibiotic therapy or, in the most severe infections, even colectomy.