Gut Microbiota Characteristics in Acute Pancreatitis Patients and Their Association with SIRS and Organ Failure: An Experimental Study.

Background: Acute pancreatitis (AP) is a common gastrointestinal disease. Systemic inflammatory response syndrome (SIRS), a severe complication of AP, increases the risk of organ failure and progression to severe AP (SAP). Gut microbiota dysbiosis is linked to AP pathogenesis. The aim of this study is to investigate the gut microbiota characteristics of AP patients and their association with SIRS and organ failure. Methods: Rectal swabs from 19 healthy controls (HC) and 88 AP patients (stratified into non_SIRS, SIRS, low/med/high_sequential organ failure assessment (SOFA) groups) were analyzed using 16S rRNA gene sequencing. Microbiota diversity, composition, and function were evaluated, and random forest diagnostic models were constructed. Results: Compared with HC, AP (SIRS/non_SIRS) patients had altered clinical indices, reduced gut microbial richness and diversity. As SOFA scores increased, the high_SOFA group exhibited further reductions in richness and diversity. Barplots analysis showed that there were differences in the mainly dominant microbiota between HC and AP (SIRS/non_SIRS) patients. Some differentially abundant genera such as Conclusion: Gut microbiota dysbiosis is correlated with the occurrence of AP, development of SIRS, and severity of organ failure. Specific microbiota taxa and functional pathways may serve as potential therapeutic targets or diagnostic biomarkers for AP, providing a microbial perspective for personalized management of this disease.