Methods: In this prospective cohort study, healthy infants attending a demographically diverse suburban pediatric practice were enrolled at birth and followed through their 2-month, 6-month, and 12-month well child visit. At each visit, stool samples were collected, and questionnaires including interim exposure to potential risk factors for CD acquisition were administered. Stool was inoculated on pre-reduced CCFA agar with a graduated loop. Among CD isolates, toxin genes were identified by PCR.
Results: Fifty infants were recruited; 90% of samples and questionnaires were completed. The average gestational age was 39 weeks and 46% were male. 28 (56%) infants had at least 1 sample positive for CD during the study: cross sectional incidence was 0/50 at birth; 9/47 (19%) at 2 months; 22/43 (51%) at 6 months; 6/37 (16%) at 1 year. Of those with positive stool cultures, 3 (11%) tested positive at multiple visits. 30/37 (81%) isolates were PCR-positive for CD toxin. 5 stool samples harbored > 4.5 log10 cfu of toxigenic CD/gm of stool. Proportions of CD+ vs CD- subjects, respectively, with interim exposure to selected CD risk factors at each visit were as follows: infant healthcare visit 45% vs 42%; household member healthcare visit 17% vs 23%; household member with diarrhea 14% vs 29%; antibiotic exposure 5 % vs 4%; antacid exposure 7% vs 3%, all P > .05. Regarding risks for acquisition of enteric pathogens in general: breastmilk-including nutrition 57% vs 73% (P < .05 only at 2-month visit); 48% CD+ infants had interim daycare attendance vs 25% CD- (but P > .05 at each visit).
Conclusion: Asymptomatic carriage of toxigenic CD occurred in over half of healthy infants during the first year of life, and several had a high organism burden that could increase the risk for transmission. While daycare attendance was more common among colonized infants, the majority of infants who were CD+ had no daycare exposure.
J. A. Clayton,
S. Senders, None
C. J. Donskey, None
P. Toltzis, None