Infants are commonly asymptomatic carriers of C. difficile (14-63%), but clinical illness is rarely reported before 12-24 months of age. It has been hypothesized that infants lack the cellular machinery for Clostridium toxin internalization. When investigating an infant with diarrhea, alternative diagnoses should be considered even with a positive test for C. difficile. Testing should be limited to immunosuppressed infants or those with underlying intestinal conditions (e.g. Hirschsprung disease, inflammatory bowel disease) when other etiologies have been ruled out. Therefore, it is prudent to avoid routine testing in children less than 12 months, and for children 1-3 years of age, test for other causes of diarrhea first, particularly viral.
Sources:
Schutze G, et al. Clostridium difficile infection in infants and children. Pediatrics. 2013 Jan;131(1):196-200. PMID: 23277317.
Allen U, et al. Clostridium difficile in paediatric populations. Paediatr Child Health. 2014 Jan;19(1):43-54. PMID: 24627655.