Gastric infection perturbs human oral microbiota.

Background: We investigated the effects of gastric infection on the daytime and overnight human oral microbiota.

Methods: Twenty four volunteers were recruited. Ten tested positive for infection by the Carbon-14 Urea Breath Test, and the rest were negative. Two oral swabs were collected: one immediately after waking up in the morning and before brushing teeth, and another in the evening before teeth-brushing. DNA extract acquired from each swab was subjected to Illumina sequencing of gene amplicons. The microbial abundance and composition were analysed in relation to infection status.

Results: -positive individuals had significant changes in the alpha and beta diversities in the daytime samples in comparison to those who were negative. To identify which taxa could be significantly affected within the cohorts in the daytime, we employed the LEfSe method. When compared against UBT-negative samples, significantly higher abundances were detected in both and , while , , and were significantly decreased in the UBT-positive samples.

Discussion: Our data demonstrated that infection affects the human daytime oral microbiota. The hitherto undocumented changes of several bacterial genera due to infection require more studies to examine their potential health effects on affected individuals.