Bibliometric analysis of research trends and hotspots on the microbial mediation effects

The microbiome is increasingly recognized as a potential mediator linking environmental exposures and host-related factors to health outcomes. However, comprehensive bibliometric assessments of microbial mediation effects remain scarce. This study analyzed 3506 eligible articles published from 2016 to 2025, retrieved from the Web of Science Core Collection and Scopus. Using CiteSpace, VOSviewer, and the Bibliometrix R package, we examined publication trends, national and institutional contributions, co-citation networks, and keyword dynamics. According to statistics, researchers from 91 countries and 1151 institutions participated in this field, with China and the United States leading in contributions. The Chinese Academy of Sciences was the most prolific institution (49 documents, 2765 citations), while the University of California system received the highest citation count (4285). Co-citation analysis yielded 653 nodes and 771 links ( $Q=0.7894$ , $S=0.9304$ ), with the largest cluster being "cancer development" (47 publications). The strongest citation burst was Belkaid and Hand (2014, Cell; burst strength = 9.54). Keyword co-occurrence analysis identified 6705 keywords, with "gut microbiota" being the most frequent; "Mendelian randomization" and "gut-brain axis" emerged as new hotspots. Overall, this study synthesizes a decade of research, demonstrating a shift from descriptive association studies to mechanistic and causal investigations of microbial mediation, in which Mendelian randomization and the microbiota-gut-brain axis have emerged as important recent research themes. These findings provide a systematic overview of the field and offer valuable insights for future research in microbiology, medicine, and ecology.