Advancements in the Pathogenesis, Diagnosis, and Therapeutic Implications of Intestinal Bacteria

Intestinal bacteria form one of the most complex microbial communities in the human body, playing a crucial role in maintaining host health and contributing to the development of various diseases. Here, we provide a comprehensive overview of the composition and function of intestinal bacteria, the factors affecting their homeostasis, and their association and mechanisms with a range of diseases (e.g., inflammatory bowel diseases, colorectal cancer, metabolic diseases). Additionally, their advanced potential in disease diagnosis and treatment is highlighted. Therapies, such as chemotherapy, radiotherapy, and immunotherapy, are significantly impacted by intestinal bacteria, with research indicating that bacteria can enhance chemoimmunotherapy efficiency by affecting T cell recruitment and immune cell infiltration. Fecal microbiota transplantation has emerged as a promising option for treating recurrent Clostridium difficile infections and certain metabolic and neurological disorders. Gut bacteria-related serum metabolites serve as non-invasive indicators for diagnosing CRC, while fecal immunochemical tests offer promising applications in CRC screening. Future research is needed to better understand the causal relationships between intestinal bacteria and diseases, develop more precise diagnostic tools, and evaluate the effectiveness and safety of microbiome-targeted therapies in clinical treatment. This study provides deeper insights into the role of intestinal bacteria in human health and disease, providing a scientific basis for innovative therapeutic strategies that have the potential to transform the landscape of healthcare.