<p class="first" id="d4953922e330">Empiric probiotics are commonly consumed by healthy
individuals as means of life quality
improvement and disease prevention. However, evidence of probiotic gut mucosal colonization
efficacy remains sparse and controversial. We metagenomically characterized the murine
and human mucosal-associated gastrointestinal microbiome and found it to only partially
correlate with stool microbiome. A sequential invasive multi-omics measurement at
baseline and during consumption of an 11-strain probiotic combination or placebo demonstrated
that probiotics remain viable upon gastrointestinal passage. In colonized, but not
germ-free mice, probiotics encountered a marked mucosal colonization resistance. In
contrast, humans featured person-, region- and strain-specific mucosal colonization
patterns, hallmarked by predictive baseline host and microbiome features, but indistinguishable
by probiotics presence in stool. Consequently, probiotics induced a transient, individualized
impact on mucosal community structure and gut transcriptome. Collectively, empiric
probiotics supplementation may be limited in universally and persistently impacting
the gut mucosa, meriting development of new personalized probiotic approaches.
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