Dysbiosis and infant colic
Infant colic remains an etiological and therapeutic enigma for health professionals. A team of French and Swiss researchers tried to find its origin in the intestinal microbiota.
Intestinal colonization occurs at a very early stage in life and starts as soon as breastfeeding begins. We now know it is a major event in the life of newborns. Infant colic might be related to the composition of the intestinal flora.
There are thousands of intestinal bacteria with a myriad of final and intermediate metabolites involved, the main one being lactate. According to the study authors, lactate is not responsible for symptoms, but it is an essential intermediate compound in the production of H2, which is the one responsible for gastrointestinal disorders. The initial assumption is that H2 production and accumulation by lactate-utilizing bacteria (LUB) are the source of infant colic. Stool samples of 40 healthy children –of which 8 had colic– were studied: the analysis of bacterial strains involved was carried out by culture and qPCR, and metabolite levels were measured by HPLC.
Imbalance between H2 production and consumption
Several bacteria were identified in the children’s stool, including Propionibacterium avidum, Eubacterium limosum, Desulfovibrio piger, Veillonella ratti, and Eubacterium hallii. In particular, children with colicky behavior had a higher level of LUB non-SRB* (H2 producers), with a predominance of V. ratti and E. hallii, than LUB SRB* (H2 utilizers) such as D. piger. These data support the assumption that there is an imbalance between H2-producing and H2-utilizing bacteria, which would lead to colic symptoms in the first months of life. In vitro studies suggest that E. limosum and D. piger coexist with V. ratti in co-cultures and could be able to decrease the amount of H2 produced by V. ratti.
Colic symptoms suggest that metabolite accumulation is only temporary. This study, which proves that there is an increase in lactate-utilizing H2-producing bacteria, might explain current therapeutic dead-ends. According to the authors, the use of probiotics or prebiotics promoting the colonization of low- or non-H2-producing bacteria (P. avidum and E. limosum) or H2-utilizing bacteria (D. piger) could counter bacteria such as Veillonella by reducing the H2 accumulation responsible for pain. However, these preventative or therapeutic methods require the identification of the bacteria and metabolites present in colicky children, something that is not currently possible in routine check-ups.
*SRB = sulfate-reducing bacteria
Pham, V. T., Lacroix, C., Braegger, C. P. & Chassard, C. Lactate-utilizing community is associated with gut microbiota dysbiosis in colicky infants. Sci Rep 7, (2017).