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

Background And Aims: 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.

Methods: 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.

Results: 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.

Conclusions: The lipid and energetic metabolic pathways were the most affected in patients with decompensated cirrhosis and those with overlapping infections.