Yanan Yuan, Ting Wu, Xiaoyun Xu
Lactobacilli represent a major group of probiotics that are widely distributed across natural environments and traditional fermented foods. Recent phylogenomic reclassification has systematically restructured the formerly heterogeneous Lactobacillus genus into 25 distinct genera, offering refined resolution of strain‑level phylogenetic diversity and functional specialization. Accumulating evidence confirms that the health-promoting effects of lactobacilli are strain-specific. Successful intestinal adhesion represents one important mechanism for exerting sustained probiotic functions, alongside contributions from secreted metabolites, bacteriocins, and microbiota-mediated interactions. This review presents a comprehensive examination of lactobacilli adhesion mechanisms, encompassing the intricate molecular interactions between bacterial adhesins and intestinal epithelial components, the integration of complementary in vitro and in vivo experimental approaches for adhesion assessment, and the multidimensional influences of bacterial physiology, host factors, and dietary modulation on adhesion efficiency. Emerging bioengineering strategies focused on strain improvement and novel delivery systems are also discussed. Collectively, this synthesis of current knowledge establishes a robust conceptual framework to guide the development of advanced lactobacilli formulations with optimized gut persistence and targeted bioactivities. The findings carry important implications for advancing precision applications of lactobacilli in nutritional, therapeutic, and functional food domains.