Development of intestinal bifidobacteria and lactobacilli in breast-fed neonates

Background & aims: Neonates are subject to numerous factors that affect normal intestinal colonization. This study was to quantify bifidobacteria and lactobacilli in the faeces of breast-fed neonates using quantitative real-time PCR assay, and to investigate the effects of different delivery on the development of bifidobacteria or lactobacilli. Methods: The faecal bifidobacteria and lactobacilli of 40 healthy breast-fed neonates were studied prospectivety. Twenty infants were vaginally delivered (VD), and 20 by caesarean delivery (CD) with prophylactically 4g intravenous cefradine administered to their mothers three times. The faecal bifidobacteria and lactobacilli of neonates were consecutively quantified by SYBR Green I-based reat-time PCR assay in the first 7 days after birth. Results: The mean levels of bifidobacteria increased from 5.1 to 9.3 in the VD group vs from less than 4.6 to 8.7 in the CD group. The bifidobacteria colonization levels in six samples in the CD group were lower than the limit of detection on day 2. The mean levels of bifidobacteria in the VD group were significantly higher than in the CD group (p < 0.05). The mean levels of lactobacilli increased from 4.9 to 7.2 in the VD group vs from 4.9 to 6.9 in the CD group. There was no statistical difference between two groups during the first week (p > 0.05). The development of bifidobacteria and lactobacilli showed significant interindividual differences in all infants studied. Conclusions: Primary intestinal bifidobacteria in neonates by caesarean may be disturbed more significantly than lactobacilli. (c) 2007 Elsevier Ltd and European Society for Clinical. Nutrition and Metabolism. All rights reserved.