From the Guidelines
Treatment is not typically recommended for patients who test positive for C. difficile antigen but negative for toxins, unless they have symptoms of C. difficile infection (CDI). This laboratory pattern indicates the presence of C. difficile bacteria but without detectable toxin production, which is what causes the disease. For asymptomatic patients, no treatment is needed as this may represent colonization rather than active infection 1. However, if a patient has symptoms consistent with CDI (such as diarrhea, abdominal pain, fever), clinical judgment should be used, and further testing with PCR for toxin genes might be warranted.
Key Considerations
- The presence of C. difficile antigen without toxin production may indicate colonization rather than infection 1.
- Asymptomatic patients do not require treatment, as it may disrupt gut flora and select for resistant organisms without providing clinical benefit 1.
- Symptomatic patients may require treatment, and oral vancomycin (125 mg four times daily for 10 days) or fidaxomicin (200 mg twice daily for 10 days) are appropriate options 1.
- Metronidazole is now considered a second-line agent due to lower efficacy and more side effects 1.
Treatment Approach
If treatment is deemed necessary based on symptoms, the following approach can be considered:
- Oral vancomycin (125 mg four times daily for 10 days) or fidaxomicin (200 mg twice daily for 10 days) as first-line treatment options 1.
- Metronidazole as a second-line agent, due to lower efficacy and more side effects 1.
- Fecal microbiota transplantation (FMT) as an effective option for patients with multiple CDI recurrences who have failed appropriate antibiotic treatments 1.
- Coadjuvant treatment with monoclonal antibodies (bezlotoxumab) to prevent recurrences of CDI, particularly in patients with CDI due to the 027 epidemic strain, in immunocompromised patients, and in patients with severe CDI 1.
From the Research
Treatment of C. difficile Infection
- The treatment of choice for C. difficile infection (CDI) is antibiotics, such as vancomycin or fidaxomicin 2, 3, 4.
- Fecal microbiota transplantation (FMT) has emerged as a promising therapy for recurrent CDI, with success rates of over 85% compared to less than 50% with antibiotics for multiple recurrent CDI 2, 3, 5.
- For patients with recurrent CDI, FMT has demonstrated higher success rates than vancomycin, fidaxomicin, or placebo 3, 5.
C. difficile Antigen Positive but Toxins Negative
- There is no direct evidence in the provided studies to support a specific treatment approach for patients who are C. difficile antigen positive but toxins negative.
- However, the studies suggest that FMT can be an effective treatment for recurrent CDI, regardless of the toxin status 3, 5.
- In one study, FMT was superior to fidaxomicin for treatment of recurrent CDI, with a combined clinical resolution and negative result from a polymerase chain reaction test for C. difficile toxin 8 weeks after treatment 5.
Treatment Options
- Vancomycin and fidaxomicin are commonly used antibiotics for treating CDI 2, 3, 4, 6.
- FMT is a promising therapy for recurrent CDI, with high success rates compared to antibiotics 2, 3, 5.
- Standardized microbiome-based therapies, such as SER-109 and RBX2660, have also shown promise in treating recurrent CDI 3.