Lactobacillus acidophilus DDS-1 Modulates the Gut Microbial Co-Occurrence Networks in Aging Mice.

Age-related alterations in the gut microbiome composition and its impacts on the host's health have been well-described; however, detailed analyses of the gut microbial structure defining ecological microbe-microbe interactions are limited. One of the ways to determine these interactions is by understanding microbial co-occurrence patterns. We previously showed promising abilities of Lactobacillus acidophilus DDS-1 on the aging gut microbiome and immune system. However, the potential of the DDS-1 strain to modulate microbial co-occurrence patterns is unknown. Hence, we aimed to investigate the ability of L. acidophilus DDS-1 to modulate the fecal-, mucosal-, and cecal-related microbial co-occurrence networks in young and aging C57BL/6J mice. Our Kendall's tau correlation measures of co-occurrence revealed age-related changes in the gut microbiome, which were characterized by a reduced number of nodes and associations across sample types when compared to younger mice. After four-week supplementation, L. acidophilus DDS-1 differentially modulated the overall microbial community structure in fecal and mucosal samples as compared to cecal samples. Beneficial bacteria such as Lactobacillus, Oscillospira, and Akkermansia acted as connectors in aging networks in response to L. acidophilus DDS-1 supplementation. Our findings provided the first evidence of the DDS-1-induced gut microbial ecological interactions, revealing the complex structure of microbial ecosystems with age.