Table 1_The oral-gastric microbial axis in children: salivary signatures as non-invasive biomarkers for pediatric gastritis and Helicobacter pylori infection.docx

We evaluate candidate salivary and oral signatures—taxonomic, H. pylori-specific, and metabolic—and grade each on two axes: the population generating the evidence (pediatric, adult, or non-human) and the stage of biomarker development reached, each tied to a stated target condition. The picture is asymmetric: the connectivity argument is well supported and the mechanistic account coherent, but the model has not been demonstrated end-to-end in children.

A few signatures have genuine pediatric support, and salivary assays targeting the H. pylori 23S rRNA gene reach the clinical-assay stage on pediatric evidence, with sensitivity of 87-94% but specificity ranging from 80% to 100% in the two cohorts with recoverable two-by-two data; no candidate has been independently validated in children, most evidence is adult-derived, and whether the oral cavity is a true H. pylori reservoir remains unresolved.

Because a single, unreplicated comparative study indicates that H. pylori remodels the gastric microbiota differently in children than in adults, adult signatures cannot be assumed transferable. We conclude that oral-gastric signatures currently suit research stratification rather than clinical decision-making, and specify the longitudinal, multi-omics, viability-resolved studies needed to advance them toward clinical validity.</p>