Overtesting and Overtreating: A Problem With C. difficile

      Testing for Clostridioides difficile should be done only for patients who have a new onset of unexplained “true diarrhea,” which means three or more loose stools in 24 hours — unformed stools that take the shape of a collection container, Ghinwa Dumyati, MD, said at the AMDA — The Society for Post-Acute and Long-Term Care Medicine’s annual conference.
      The need to more carefully screen is one of the “biggest issues” with C. difficile testing today, said Dr. Dumyati, who directs the Rochester (N.Y.) Nursing Home Collaborative, part of a larger citywide initiative to prevent C. difficile ( “We’re testing everyone and they’re positive, just as with urinary tract infections, and we might be giving them antibiotics they don’t need … You could even end up putting people in isolation who don’t need to be.”
      She issued one more plea: To not perform repeat testing. “There is no test of cure,” said Dr. Dumyati, who is also a professor of medicine at the University of Rochester Medical Center. “Because once you have C. difficile, you can be colonized for [at least] several weeks afterwards.”
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      The need for more careful screening is one of the “biggest issues” with C. difficile testing today.
      Photo by Michael Schiffer on Unsplash
      Toxin EIA tests, which detect free toxins, have low sensitivity and moderate specificity. GDH EIA tests, which detect the common C. difficile antigen, have high sensitivity but low specificity. “That’s why there’s been a push overall to do PCR [polymerase chain reaction],” Dr. Dumyati explained. In the Rochester community, she said, “some do just the PCR, and others [take a multistep approach].”
      The most recent guidelines for C. difficile infection from the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA) were published last year (Clin Infect Dis 2018;66:e1–e48).
      Vancomycin or fidaxomicin are the drugs of choice for an initial episode of C. difficile infection, and metronidazole is recommended only for mild disease or when access to the other drugs is limited. The newer antibiotic fidaxomicin has less of an effect on the microbiome and has been associated with a nearly 10% reduction in recurrence. “The issue,” Dr. Dumyati said, “is the cost … $3,600 for 10 days.”
      Fecal microbiota transplantation is recommended for patients with multiple recurrences who have failed antibiotic regimens. And, although it’s not included in the IDSA/SHEA guidelines, bezlotoxumab, a human monoclonal antibody that binds to C. difficile toxin B and neutralizes its effect, is another choice for recurrent disease, Dr. Dumyati said. Research has shown that bezlotoxumab does not influence cure rates significantly in patients with C. difficile infection on standard-of-care therapy, but it does reduce the incidence of recurrence (Biologics 2018;12:11–21).
      “The issue with bezlotoxumab right now is, we don’t really know where to use it,” she said. “There’s evidence that it could be used in a population of elderly with multiple recurrences, or the immunocompromised … We’ve struggled in our hospital to put guidelines together about who should get it and not get it.”
      Among the risk factors for recurrences are an infection caused by a BI/NAP1/027 strain, and continued administration of other antimicrobials during or after initial treatment of the C. difficile infection, Dr. Dumyati said.