Intestinal colonization with Clostridium difficile in infants up to 18 months of age.

The faecal colonization with Clostridium difficile was investigated among 343 infants during their first 18 months of life. Rectal swabs were taken at the ages of 6 days, 6 weeks, 6 months, 11 months and 18 months. About 25% of the children were colonized with Clostridium difficile between 6 days and 6 months of age. The colonization rate decreased to 3% at 18 months of age. The rate of strains producing cytotoxin was low in infants less than 6 months of age, but at that age about half of the strains isolated were toxin-producing. Breast-fed children were significantly less often colonized with Clostridium difficile than were bottle-fed infants, both at 6 weeks of age (21% versus 47%, p less than 0.05) and at 6 months of age (19% versus 39%, p less than 0.001). Colonization with Clostridium difficile at 6 months of age was associated with a greater frequency of diarrhoeal disease between 6 and 11 months of age (27% versus 16%, p less than 0.05). This association was even more pronounced when the bacteria persisted at 11 months of age (54%, p less than 0.01). Antibiotic therapy could not be demonstrated to influence colonization with Clostridium difficile at any age.