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ARS Home » Pacific West Area » Davis, California » Western Human Nutrition Research Center » Diet, Microbiome and Immunity Research » Research » Publications at this Location » Publication #408712
Research Project: Impact of Diet on Intestinal Microbiota, Gut Health and Immune Function

Location: Diet, Microbiome and Immunity Research

Title: Stool microbial composition is associated with recent and future diarrhea and fever events in breastfed Danish infants

Author
item Coates, Laurynne
item Storms, David
item Spearman, Sarah
item Shahab-Ferdows, Setareh
item CHRISTENSEN, SOPHIE - University Of Copenhagen
item LEWIS, JACK - University Of Copenhagen
item MOLGAARD, CHRISTIAN - University Of Copenhagen
item MICHAELSEN, KIM - University Of Copenhagen
item Allen, Lindsay
item Lemay, Danielle
item Kable, Mary

Submitted to: mSystems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2026
Publication Date: 5/11/2026
Citation: Coates, L.C., Storms, D.H., Spearman, S., Shahab-Ferdows, S., Christensen, S.H., Lewis, J., Molgaard, C., Michaelsen, K.F., Allen, L.H., Lemay, D.G., Kable, M.E. 2026. Stool microbial composition is associated with recent and future diarrhea and fever events in breastfed Danish infants. mSystems. https://doi.org/10.1128/msystems.00134-26.
DOI: https://doi.org/10.1128/msystems.00134-26

Interpretive Summary: Diarrhea continues to be a significant cause of ill health among infants in high-income countries. However, the role played by the microbial community that is developing in the infant gut as they grow is not fully understood, especially for well-nourished and breastfeeding infants. A type of bacteria that is typically found in the mouth of infants, Granulicatella, was greater in abundance of stool from Danish infants that had diarrhea. This bacteria has the potential to be pathogenic, which suggests further research is needed to determine its possible role in, and impact on recovery from diarrhea.

Technical Abstract: Background: Diarrhea is a major cause of morbidity among infants in high-income countries, including Denmark. There are many cases of diarrhea among children in Denmark for which no etiological agent is detected. Objectives: This study investigated the associations between diarrhea and the gut microbial community in well-nourished, breastfeeding Danish infants. Methods: Stool samples were collected from infants at three time points during the first 8.5 months of life. For each stool sample, a matching infant morbidity questionnaire and infant diet/breastfeeding questionnaire was completed by the mother with staff guidance. Stool samples were frozen soon after collection and later extracted for total microbial DNA. The V4-V5 region of the 16S rRNA gene was amplified and sequenced with Illumina MiSeq. QIIME2 was employed to identify amplicon sequence variants and align them to reference sequences from the SILVA database. PERMANOVA was used to test for relationships between diarrhea and beta-diversity. Linear mixed effects modeling was used to test for associations between diarrhea and alpha-diversity. ANCOM-BC2 was used to identify stool microbial taxa differentially abundant with diarrhea. All models included covariates known or suspected of impacting the stool microbiota. Results: Beta-diversity was not associated with diarrhea. Alpha-diversity was negatively associated with antiobitic use and with diarrhea, but was positively associated with age. Granulicatella abundance was positively associated with diarrhea. Stool alpha diversity and microbial abundance during the first 3.5 months of life were not associated with future diarrhea during 3.5 – 8.5 months of age. Conclusions: These findings build on previous work demonstrating a negative relationship between stool microbial alpha-diversity and diarrhea, and a positive association between Granulicatella and diarrhea. Importantly, this study reveals diarrhea is associated with stool Granulicatella in well-nourished, breastfeeding Danish infants like it is in children from low-income countries.