Updated guidelines on the diagnosis and treatment of Clostridium difficile (C. diff.) by IDSA and the Society for Healthcare Epidemiology of America (SHEA) have published in Clinical Infectious Diseases. Diagnosis and treatment of C. diff. has evolved significantly since the last guidelines were published in 2010.

C. diff. is diagnosed based on a patient’s medical history, signs and symptoms, combined with test results. The optimal method for laboratory diagnosis of C. diff. is the subject of debate and depends on how carefully patients are selected for testing. The updated guidelines recommend only testing patients with new onset and unexplained diarrhea (three or more unformed stools in 24 hours).

While immunoassays were the most common diagnostics employed previously, molecular testing – which has its pros and cons – is now used by more than 70 percent of hospital labs. Molecular tests can help rule out C. diff. infection, as well as reduce transmission by detecting C. diff. colonization in patients with diarrhea from other causes. But because they are very sensitive and can lead to over diagnosis, when there are no pre-agreed institutional criteria that limit testing to patients with significant unexplained diarrhea of three or more unformed stools in 24 hours, the guidelines recommend that a C. diff. common antigen test and a stool toxin test (such as an immunoassay) be used as part of a two- or three-step test process.

Not everyone diagnosed with C. diff. requires treatment. The guidelines include new recommendations for treatment when warranted, including:

  • Vancomycin or fidaxomicin – Antibiotics vancomycin or fidaxomicin should be used for initial treatment of even mild C. diff., rather than metronidazole, which the previous guidelines recommended as first-line therapy. Research shows the cure rates are higher for vancomycin and fidaxomicin than for metronidazole.
  • Fecal microbiota transplantation (FMT) – The guidelines recommend FMT for treatment of people with two or more recurrences of C. diff. and for whom traditional antibiotic treatment has not worked. FMT is a new treatment since the last guidelines were published but is not approved by the Food and Drug Administration (FDA). However, FDA has issued Guidance for Industry regarding the use of FMT to treat C. diff. infection not responsive to standard therapies. FMT involves transferring fecal bacteria from a healthy person’s stool to the gut of a person with recurrent C. diff., to replenish the good bacteria and control the disease-causing bacteria.

The guidelines include the same suggestions for preventing the spread of C. diff. as the 2010 guidelines – including isolating infected patients and ensuring healthcare workers and visitors use gloves and gowns – but also call for increased attention to antibiotic stewardship to reduce the unwarranted use of the drugs. While nearly all antibiotics predispose people to C. diff., some are of particular concern, including the fluoroquinolones, cephalosporins and clindamycin.

The new guidelines also include recommendations for epidemiologic surveillance, diagnosis, and treatment of C. diff. in children, which the 2010 guidelines did not address.

The IDSA/SHEA guidelines panel was co-chaired by L. Clifford McDonald, MD; Dale N. Gerding, MD, FIDSA; and Stuart Johnson, MD, FIDSA. Panel members included: Johan S. Bakken, MD, PhD, FIDSA; Karen C. Carroll, MD, FIDSA, Susan E. Coffin, MD, FIDSA; Erik R. Dubberke, MD, MSPH, FIDSA; Kevin W. Garey, PharmD, MS; Carolyn V. Gould, MD; Ciaran Kelly, MD; Vivian Loo, MD; Julia Shaklee Sammons, MD, MSCE; Thomas J. Sandora, MD, MPH; and Mark H. Wilcox, MD.