RT Journal Article SR Electronic T1 Gut microbiota composition and development of atopic manifestations in infancy: the KOALA Birth Cohort Study JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 661 OP 667 DO 10.1136/gut.2006.100164 VO 56 IS 5 A1 John Penders A1 Carel Thijs A1 Piet A van den Brandt A1 Ischa Kummeling A1 Bianca Snijders A1 Foekje Stelma A1 Hanne Adams A1 Ronald van Ree A1 Ellen E Stobberingh YR 2007 UL http://gut.bmj.com/content/56/5/661.abstract AB Background and aims: Perturbations in intestinal microbiota composition due to lifestyle changes may be involved in the development of atopic diseases. We examined gut microbiota composition in early infancy and the subsequent development of atopic manifestations and sensitisation. Methods: The faeces of 957 infants aged 1 month and participating in the KOALA Birth Cohort Study were analysed using quantitative real-time PCR. Information on atopic symptoms (eczema, wheeze) and potential confounders was acquired through repeated questionnaires. Total and specific IgE were measured in venous blood samples collected during home visits when the infant was 2 years old. During these home visits a clinical diagnosis of atopic dermatitis was made according to the UK-Working Party criteria. Results: The presence of Escherichia coli was associated with a higher risk of developing eczema (ORadj = 1.87; 95% CI 1.15 to 3.04), this risk being increased with increasing numbers of E coli (pfor trend = 0.016). Infants colonised with Clostridium difficile were at higher risk of developing eczema (ORadj = 1.40; 95% CI 1.02 to 1.91), recurrent wheeze (ORadj = 1.75; 95% CI 1.09 to 2.80) and allergic sensitisation (ORadj = 1.54; 95% CI 1.02 to 2.31). Furthermore, the presence of C difficile was also associated with a higher risk of a diagnosis of atopic dermatitis during the home visit (ORadj = 1.73; 95% CI 1.08 to 2.78). Conclusion: This study demonstrates that differences in gut microbiota composition precede the development of atopy. Since E coli was only associated with eczema and C difficile was associated with all atopic outcomes, the underlying mechanisms explaining these association may be different.