An infection trial showed that L. reuteri SLZX19-12 has superior ability to prevent the invasion by S. Typhimurium SL1344 of the colon and can defend against the inflammation induced by the S100A8/S100A9–NF-κB pathway and potential apoptosis, in which the enhanced stability of the gut microbiota may be one of the main mechanisms. The gene discussed is S100A8; the disease is infection.