Updated C. difficile guidelines address changes in disease strain, drug effectiveness
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Two professional societies have issued updated Clostridium difficile guidelines to address epidemiologic and treatment changes since guidelines were first released in 1995.
In the last 15 years, researchers have identified a more virulent strain of C. difficile and have published data on the decreased effectiveness of metronidazole in severe disease, said the update by the Society for Healthcare Epidemiology of America and the Infectious Diseases Society of America. The update was published in the May Infection Control and Hospital Epidemiology. Recommendations include:
- While stool culture is the most sensitive test, it is not clinically practical due to slow turnaround time. Toxin testing is most important clinically, but lacks sensitivity. A potential strategy is to employ a two-step method that uses enzyme immunoassay testing of glutamate dehydrogenase (GDH) as initial screening, and then uses the cell cytotoxicity assay or toxigenic culture as the confirmatory test for GDH-positive stool specimens. Results seem to differ based on the GDH kit used, so this is an interim recommendation.Polymerase chain reaction (PCR) testing seems to be rapid, sensitive and specific, but more data are needed before it can be recommended for routine testing.Repeat testing during the same episode of diarrhea is discouraged, as it has limited value.Use metronidazole for an initial episode of mild-to-moderate C. difficile infection (CDI). The dosage is 500 mg orally three times per day for 10 to 14 days.For an initial episode of severe CDI, use vancomycin. The dosage is 125 mg orally four times per day for 10 to 14 days.For the first recurrence of CDI, usually use the same regimen as the initial episode, though stratify by disease severity. For the second or later recurrence, use vancomycin with a tapered and/or pulse regimen. Don't use metronidazole after the first recurrence or for long-term chronic therapy, due to the potential for cumulative neurotoxicity.