Gut microbiota dysbiosis in sepsis: mechanisms and the gut-organ axis with a focus on lung and brain interactions.

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, with its high mortality closely linked to complex pathophysiological processes. In recent years, the gut microbiota, as the largest human micro-ecosystem, has garnered increasing attention for its critical role in the onset, progression, and prognosis of sepsis. This narrative review summarizes recent research advances, with a particular focus on studies published over the past 3 years, while incorporating selected earlier studies to provide essential mechanistic background. It first delves into the pathophysiological mechanisms underlying sepsis-induced gut microbiota imbalance, highlighting key factors such as intestinal barrier disruption, immune-microbiota interaction disturbances, and alterations in microbial metabolites. Subsequently, the review comprehensively evaluates clinical diagnostic biomarker potentials and therapeutic strategies centered on gut microbiota modulation, including probiotics, prebiotics, fecal microbiota transplantation, and targeted interventions on microbial metabolites. Finally, current research challenges and future translational directions are discussed, aiming to provide novel theoretical foundations and strategic insights for precise prevention and treatment of sepsis. However, most microbiota-targeted therapeutic strategies remain at the preclinical or early clinical stage, and their efficacy and safety in sepsis require further validation.