Polymerase chain reaction test for clostridium difficile toxin B gene reveals similar prevalence rates in children with and without inflammatory bowel disease

Objective: Clinicians often evaluate for Clostridium difficile infection (CDI) in patients with inflammatory bowel disease (IBD) presenting with exacerbations. A highly sensitive polymerase chain reaction (PCR) test for the toxin B gene of C difficile is increasingly used to diagnose CDI. The aim of this study was to determine the prevalence of positive C difficile PCR results in children and young adults with and without active IBD compared with patients with non-IBD gastrointestinal disease. Methods: Fecal samples were obtained from patients with ulcerative colitis (UC, n=76) or Crohn disease (CD, n=69) and 51 controls followed in our gastroenterology program. Samples were analyzed for C difficile using a PCR test for the C difficile toxin B gene (BD GeneOhm Cdiff assay). Proportions of positive tests in each group were compared using the Pearson χ test. Results: The prevalence of positive PCR results was 11.6% in patients with CD, 18.4% in patients with UC, and 11.8% in controls (P=0.25). There were no significant differences in the prevalence of positive C difficile results among patients with IBD with and without active disease or among patients with and without diarrhea. Conclusions: Positive C difficile PCR results occur with similar frequency in patients with IBD with and without active disease and in patients with other gastrointestinal diseases. A positive result in a highly sensitive PCR assay that detects low copy numbers of a toxin gene in C difficile may reflect colonization in a subset of patients with IBD, confounding clinical decision making in managing disease exacerbations.