Synergism and antagonism in intestinal microbial communities in closed organized collectives

Introduction. The gut microbiota represents the largest part of the entire human microbiome. The formation of a stable microbiota begins at childbirth, continuing to change during life influenced by various exogenous and hereditary factors. One of such external cues is presented by closed organized collectives, where different individuals, due to the common way of life and nutrition, undergo a restructuring of the intestinal microbial communities. In addition to microbiota quantitative and qualitative changes, inter-microbial communities may also be altered (synergism, antagonism, mutualism). The aim of the study was to analyze the synergistic and antagonistic relationships between intestinal microbial communities in individuals from closed organized collectives.

Materials and methods. The study group included 120 male subjects aged 18 to 22 years, who lived within the same closed organized collectives for 9 months. Fecal samples were selected for plating prior to living in closed organized collectives (stage 1), and 9 months afterwards (stage 2). The identified microorganisms were assigned to the permanent, supplementary, or random microbiota group. To assess the relationship between pairs of genera, the Jaccard index was calculated.

Results. The results of the study showed that the synergistic relationships between members of the permanent microbiota remain stable or increase over time, which generally corresponds to the data on the properties of the obligate microbiota. Positive synergistic relationships with additional microbiota have also been identified, e.g., between Bifidobacterium spp. and the order of Lactobacillales. The synergy of these genera can effectively support normal gastrointestinal tract functioning. However, antagonistic relationships were also noted, especially between some representatives of the additional and permanent microbiota, such as Klebsiella spp. Such data may indicate a negative effect of certain microorganisms on the intestinal microbiota in a limited collective setting.

Conclusion. Further research in this field may help explain changes in microbial communities in organized collectives and develop strategies for healthy microbiota maintenance therein.