{
  "abstract": "Background Gastric precancerous lesions (GPL) represent a critical and reversible node in Correa’s cascade. The role of non-Helicobacter pylori pathogens, such as Streptococcus anginosus(S. anginosus), in the progression of GPL is increasingly recognized. Probiotics derived from the gastric microbiota may offer unique advantages for targeted regulation of gastric pathogens. This study aims to investigate the preventive and therapeutic effects and mechanisms of the gastric-derived Limosilactobacillus fermentum LAF-09 on S. anginosus-associated GPL.Methods C57BL/6 mice were randomly divided into control group, S. anginosus group, LAF-09 group, and ATCC14931 standard strain group. Following antibiotic pretreatment, a GPL model associated with S. anginosus infection was established by alternating gavage of N-methyl-N-nitrosourea (MNU) and the respective bacterial suspensions. Gastric tissues were collected at the experimental endpoint. The intervention effects were evaluated using histopathological staining, immunohistochemistry, Western Blot, fluorescence in situ hybridization (FISH), and 16S rRNA sequencing.Results S. anginosus infection successfully induced atrophic gastritis and intestinal metaplasia in mice. Gastric-derived LAF-09 significantly improved gastric mucosal structural integrity and reduced the Ki-67 proliferation index, demonstrating superior efficacy compared to the ATCC14931 group. LAF-09 effectively inhibited S. anginosus colonization, upregulated tight junction proteins and E-cadherin, and downregulated Vimentin, thereby preserving barrier function and suppressing epithelial-mesenchymal transition (EMT). 16S rRNA sequencing revealed that LAF-09 restored microbial diversity, reduced Streptococcus abundance, and enriched beneficial Lactobacillus species, exhibiting superior microbiota modulation capability compared to ATCC14931.Conclusions Gastric-derived Limosilactobacillus fermentum LAF-09 effectively prevents and treats S. anginosus-associated gastric precancerous lesions by inhibiting S. anginosus colonization, repairing the mucosal barrier, suppressing epithelial-mesenchymal transition, and maintaining gastric microbiota homeostasis.",
  "authors": [
    {
      "affiliations": [
        "Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, China"
      ],
      "name": "Jixiang Yang"
    },
    {
      "affiliations": [
        "The First Clinical Medical College, Southern Medical University, China"
      ],
      "name": "Mingfei He"
    },
    {
      "affiliations": [
        "Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, China"
      ],
      "name": "Jiechang Zhang"
    },
    {
      "affiliations": [
        "Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, China"
      ],
      "name": "Zhenhui Chen"
    },
    {
      "affiliations": [
        "Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, China"
      ],
      "name": "Hongying Fan"
    }
  ],
  "title": "IDDF2026-ABS-0179 Study on the preventive and therapeutic effects of gastric-derived limosilactobacillus fermentum LAF-09 on streptococcus anginosus-associated gastric precancerous lesions",
  "uid": "53199eb6-416a-5b17-83a6-aaf84dea24dd"
}