Clostridioides difficile Infection (CDI)
Important points:
– Clostridioides (formerly Clostridium) difficile, or in short ‘C.diff’, is the most common cause of antibiotic-associated diarrhea.
– C. diff is an occasional constituent of the gut microbiome.
– C. difficile can produce two toxins – Toxin A and Toxin B.
– Antimicrobial therapy alters the composition of the gastrointestinal flora and thus facilitates colonization with toxigenic C. difficile if the patient is exposed to C. difficile spores. This leads to C. difficile infection (CDI).
– The combination of toxin production and the ability to produce environmentally stable spores accounts for the clinical features and transmissibility of CDI.
– A hypervirulent strain of C. difficile, ribotype 027, has emerged, which produces more toxins and more severe disease than other C. difficile strains.
– Treated with stopping offending antibiotic, giving IV fluids, oral vancomycin (+ IV Metronidazole in severe cases)
What is Clostridioides difficile?
Clostridioides difficile is a gram-positive anaerobic bacillus. It is the most common healthcare-associated pathogen.
Where does it live?
Clostridioides difficile is part of colonic flora in 2–5% of healthy adults, and 20–40% of hospitalized adults.
If it is part of colonic flora in some individuals, when does it cause the disease?
With use of antibiotics, normal colonic flora is altered and competing for colonic flora is lost. C diff converts to a vegetative (growth) state with the production of enterotoxins A and B, causing colitis.
What are the clinical features of C. diff infection (CDI)?
CDI presentation is variable from being asymptomatic to fulminant colitis.
There is lower abdominal pain, watery diarrhea usually greenish in color, sometimes bloody diarrhea mimicking ulcerative colitis. There may be fever, ileus, toxic megacolon.
Colitis is called pseudomembranous colitis because there are pseudomembranes visible on endoscopy.
Consider CDI in all diarrhea associated with antibiotic use, especially if there is marked neutrophilia.
How can it be diagnosed?
Screening for the presence of C. diff can be done by immunoassay for glutamate dehydrogenase (GDH, which is a common antigen) and it detects all strains of C. difficile.
Diagnosis of CDI depends on the detection of toxins (by toxin immunoassay, or toxin gene nucleic acid amplification) which distinguishes infection from the carriage.
When do we call CDI as severe?
CDI is severe when WCC is >15 x 10^9/L or there is AKI or colitis or temperature >38.5 C.
How CDI is treated?
• Stop the offending antibiotic.
• Isolate the patient and apply contact precautions. Hand wash with soap shall be done before and after handling patient/surroundings as C. diff spores cannot be sanitised with alcohol-based gels.
• IV fluids for rehydration
• Antibiotics for CDI:
– Mild/moderate: metronidazole PO was used previously. Recently the drug of choice is oral Vancomycin 125 mg 6 hourly.
– Severe disease – Vancomycin PO or fidaxomicin. Non-responders can be started on high-dose vancomycin and IV metronidazole. Fidaxomicin can also be used.
How is the recurrent CDI treated?
Recurrent CDI is treated with weaning dose of vancomycin, fidaxomicin, and resistant cases by fecal transplantation.
Remember the mnemonic SIGHT for CDI
Suspect, Isolate within 2h, Gloves and aprons, Hand wash with soap, Test immediately.
