Blood Metabolomic Signatures to Identify Bacterial Infection in Patients with Decompensated Cirrhosis.

Bacterial infections are associated with high mortality rates in patients with decompensated cirrhosis. Early diagnosis with the available diagnostic tools is challenging. Metabolomics is a novel technique with a widespread application in hepatology. The aims of our study were to find new biomarkers for decompensated cirrhosis and for those with overlapping bacterial infections. 43 patients with compensated and 54 patients with decompensated cirrhosis were enrolled in the study. In patients with decompensation, a complete infectious workup was performed at admission. Blood and ascitic fluid were collected and stored at -80° C until performing the metabolomic analysis. Statistical analysis was performed using the Metaboanalyst 4.0 software. 36 patients (66%) in the decompensated group were infected. Among them, 15 had multiple infections; thus, finally, 52 infections were diagnosed. The main metabolic pathways affected in patients with decompensated cirrhosis were those related to lipid metabolism, involving acylcarnitines, stearic acid derivatives, and 12/15 HETE-GABA. N-oleoyl ethanolamine was the most promising biomarker for bacterial infection diagnosis. Moreover, prostaglandin E2/D2/H2 and N-oleoyl alanine levels were higher in Gram- positive infections and ceramides (d16:2/18:0), in Gram-negative infections, respectively. L-phenylalanine (m/z=166.09) and lysophosphatidylethanolamine (18:3/0:0) were the two most relevant identified ascitic biomarkers for spontaneous bacterial peritonitis diagnosis. The lipid and energetic metabolic pathways were the most affected in patients with decompensated cirrhosis and those with overlapping infections.