C. Diff Flashcards
How is C. Diff transmitted?
C. diff is transmitted person-to-person via fecal-oral route through the ingestion of spores.
Which strains of C. diff are associated with higher severity of infection?
BI/NAP1/027
Which antibiotics are associated with high risk for C. diff?
list classes and specific drugs
- fluoroquinolones
- clindamycin
- 3rd/4th gen cephs (ceftriaxone)
- carbapenems
How is CDI diagnosed?
symptoms + testing
What are the signs and symptoms of CDI?
- profuse, watery (or mucoid green), foul-smelling diarrhea
- abdominal pain
Other signs and symptoms include: fever, leukocytosis, hypoalbuminemia, acute kidney injury
Which testing methods are recommended for CDI?
- NAAT
- Antigen (GDH) test + Toxin A/B test
- NAAT + Toxin A/B test
- NAAT shows if C. diff is present or not
- GDH is an enzyme in C. diff, so the GDH test also can determine if C. diff is present
- Toxin A/B test shows whether or not the C. diff is producing toxins. If it is negative, the patient might have a colonization instead of an infection.
Do we repeat C. diff testing within 7 days of the same episode of diarrhea?
No. It has limited value and is not recommended.
It is also not recommended to test asymptomatic patients or samples with formed stools
How would you interpret the following C. difficile testing results?
- GDH antigen (+)
- toxin test (-)
- c. difficile NAAT (+)
C. diff is present, but it is not creating toxins. This means the patient is less likely to have an infection.
How is CDI classified?
- A patient with non-severe C. diff will present with WBC less than 15,000/mcL and Scr less than 1.5 mg/dL
- A patient with severe C. diff will present with WBC greater than 15,000/mcL and SCr greater than 1.5 mg/dL
- A patient with fulminant C. diff will present with hypotension or shock, ileus, and/or toxic megacolon
- Fulminant C. diff is not very common.
- Toxic megacolon has a high mortality rate.
- ileus = obstruction in ileum
What are the treatment options for CDI?
- oral vancomycin
- fidaxomicin
- metronidazole (IV or PO)
- Oral vancomycin provides broad spectrum coverage and is the standard of care
- Fidaxomicin covers a narrower spectrum but has higher rates of sustained response
- Metronidazole is reserved for fulminant cases as an additional agent
What are the advantages and disadvantages for oral vancomycin?
Advantages: poor oral absorption, manageable copay
Disadvantages: QID dosing, liquid is $ and requires PA
What are the advantages and disadvantages of fidaxomicin (Difcid)?
Advantages: poor oral absorption, higher rates of sustained tx response, lower recurrence rates, BID dosing
Disadvantages: COST
What are the advantages and disadvantages of metronidazole?
Advantages: not as costly
Disadvantages: high oral absorption, less efficacious, higher risk for recurrence
What is the treatment duration for C. diff?
10 days
What are the risk factors for CDI recurrence?
- Age > 65 years
- immunocompromised
- severe CDI on presentation
What agents can be given to reduce recurrence of CDI?
- Rebyota - fecal microbiota suspension
- Vowst - bacterial spore suspension
- Bezlotoxumab - monoclonal antibody
When would Rebyota be administered to reduce CDI recurrence?
Fecal microbiota suspension
24-72 hours after treatment completion
150 mL administered via rectal tube
When would Vowst be administered to reduce CDI recurrence?
Bacterial spore suspension
Modulates bile acid concentrations and restore fatty acids, which results in resistance to C. diff colonization and restoration of the gut microbiome
2-4 days after treatment completion
4 capsules PO QD x 3 days
When would bezlotoxumab (Zinplava) be administered to reduce CDI recurrence?
monoclonal antibody targeting C. diff toxin B to neutralize its effect
One dose during the course of CDI treatment
10 mg/kg IV x 1 dose
How do you treat CDI recurrence?
Use either vanc or fidaxomicin. Use whichever agent you didn’t use the first time.
