Fig. 4: Visual depiction of the potential oral–gastric microbial axis.

Six aspects to explore the unknown universe of oral–gastric microbes. New technology and standardized metrics are called on to identify potential pathogenetic microbes and their core microbiota, location, interaction, effect, richness and colonization (CIRCLE). Prospective solutions to these issues are listed on the left. ISH, in situ hybridization; SRT, spatially resolved transcriptomics; SAHMI, single-cell analysis of host–microbiome interactions; WGS, whole-genome sequencing; WES, whole-exome sequencing; RNA-seq, whole-transcriptome sequencing.