Abundance and Diversity of Hydrogenotrophic Microorganisms in the Infant Gut before the Weaning Period Assessed by Denaturing Gradient Gel Electrophoresis and Quantitative PCR.

摘要

Delivery mode (natural vs. cesarean) and feeding type (breast vs. formula feeding) are \udrelevant factors for neonatal gut colonization. Biomolecular methods have shown that \udthe ecological structure of infant microbiota is more complex than previously proposed, \udsuggesting a relevant presence of unculturable bacteria. It has also been postulated \udthat among unculturable bacteria, hydrogenotrophic populations might play a key role \udin infant health. Sulfate-reducing bacteria (SRB), acetogens, and methanogenic archaea \uduse hydrogenotrophic pathways within the human colon. However, to date, few studies \udhave reported detection of hydrogenotrophic microorganisms in newborns, possibly \udbecause of limitations on available group-specific, culture-independent quantification \udprocedures. In the present work, we analyzed 16 fecal samples of healthy babies aged \ud1–6 months by means of quantitative PCR (qPCR) targeting the 16S rRNA or metabolic \udfunctional genes and by denaturing gradient gel electrophoresis (DGGE). qPCR data \udshowed quantifiable levels of methanogens, SRB, and acetogens in all samples, indicat-\uding that the relative abundances of these microbial groups were not affected by delivery \udmode (natural vs. caesarian). DGGE revealed a high prevalence of the \udBlautia\ud genus \udwithin the acetogenic bacteria despite strong interindividual variability. Our preliminary \udresults suggest that hydrogenotrophic microorganisms, which have been a neglected \udgroup to date, should be included in future ecological and metabolic studies evaluating \udthe infant intestinal microbiota.