Clostridioides (previously Clostridium) difficile (C. diff) is the most common cause of diarrhea among hospitalized patients and the most commonly reported bacteria causing infections in hospitals. In a 2019 report, the CDC referred to C. diff as “an urgent threat.”
Who is most at risk?
C. diff infection (CDI) occurs more commonly following antibiotic therapy or hospitalization, and among older adults or patients with weakened immune responses. In 2002, an epidemic strain of C. diff emerged, causing more severe disease with inflammation of the colon (colitis) and an increase in deaths. This strain adheres better to the intestine and produces more toxin, which is responsible for causing illness. Non-epidemic strains may cause less severe disease.
What makes C. diff so difficult to treat?
A high relapse rate poses challenges to treating people with CDI. Recurrence of diarrhea following initial treatment occurs in about 20% of cases. The risk of yet another relapse is even greater in the weeks following treatment for a recurrent CDI.
C. diff produces spores (dormant cells capable of surviving harsh conditions for prolonged periods) that can contaminate the environment. Spores are hearty and resistant to routine cleaning. But enhanced protective measures — careful hand washing, isolation precautions for infected patients (private room, gown, and gloves), and cleaning with agents capable of killing C. diff spores — are effective ways to prevent transmission and control CDI.
Antibiotics disrupt the healthy gut bacteria (microbiome), which then provides suitable conditions for ingested spores to flourish and result in CDI.
Hospitalized patients are at greater risk, although healthy individuals in the community who have not been treated with antibiotics can also become infected.
The World Society of Emergency Surgery released updated clinical practice guidelines in 2019, focusing on CDI in surgical patients. Surgery, particularly gastrointestinal surgery, is a known risk for CDI. (Ironically, surgery is also a potential treatment option for severe CDI.)
What is the difference between C. diff colonization and C. diff infection?
Up to 5% of people in the community, and an even greater percentage of people who are hospitalized, may be colonized with C. diff bacteria, but not experience any symptoms. The risk of progressing to disease varies, since not all C. diff strains produce toxin that makes you sick. People colonized with a non-toxin-producing strain of C. diff may actually be protected from CDI.
CDI is diagnosed based on symptoms, primarily watery diarrhea occurring at least three times a day, and stool that tests positive for C. diff. A positive test without symptoms represents colonization and does not require treatment. Patients colonized with toxin-producing strains are at risk for disease, particularly if exposed to antibiotics.
How is C. diff treated?
The most common antibiotics used to treat CDI are oral vancomycin or fidaxomicin. Extended regimens, lasting several weeks, have been used successfully to treat recurrences. Van