Clostridium difficile (C. Difficile) is a spore-forming bacterium that is the leading cause of nosocomial (hospital-acquired) diarrhea. CDAD (C. Difficile associated diarrhea) – or CDI for C. difficile infection – can be a severe and life-threatening disease. It results from the overgrowth of toxin-producing strains of C. difficile in the colon, which often occurs during or after therapy with broad-spectrum antibiotics.
CDAD is a major healthcare problem. It is the number one hospital-acquired infection in the United States and leads to 29,000 deaths each year, according to the Centers for Disease Control and Prevention. The frequency and severity of CDAD has increased globally in recent years, and new hypervirulent strains of C. difficile have been discovered. They are characterized by an overproduction of toxins and other virulence factors, and by acquired resistance to fluoroquinolones – antibiotics that are commonly used to treat this type of infection.
Current antibiotic therapies for CDAD include vancomycin and metronidazole. While cure rates are generally 75-85%, there are recurrence rates of 20-30% with either drug. C. difficile spores that are resistant to antibiotic treatment and routine disinfection and therefore survive in the gut of patients and/or in the hospital environment may play a major role in the high recurrence rates after antibiotic treatment.
Only one new antibiotic, fidaxomicin, has been approved over the last 30 years for CDAD, and there remains a need for new drugs with improved properties, in particular for antibiotics that allow effective treatment of infections caused by hypervirulent strains and have low recurrence rates.
A new treatment approach for CDAD is Fecal Microbiota Transplantation (FMT), a procedure in which bacteria from fecal matter from a healthy donor are extracted and transferred to the CDAD patient with via colonoscopy and other routes of administration. It is believed that FMT works by repopulating the patient’s gut with “good” bacteria that competitively exclude C. difficile. Although FMT has proven to be an effective tool for treating CDAD, there are also significant risks, including the contamination of the donor material.