Metabolite analysis is a promising method and is increasingly being used to identify dysfunctions of various organs in patients. One of the sources of metabolites in the body is the gut microbiota. An increase in sepsis-associated aromatic microbial metabolites is a prognostically unfavorable factor and increases the risk of death in patients with sepsis.

The aim of this work was to evaluate the composition and function of the gut microbiota in patients with sepsis compared to healthy donors using chromatograph mass spectrometry.

The study included 10 patients with sepsis and 9 healthy donors, comparable in gender and age. The incubation of feces samples was carried out in thioglycollate medium (TG (at 37 ℃)) with the addition of sepsis-associated microbial metabolites (25 μM phenyllactic acid (PLA) or 25 μM 4-hydroxyphenyllactic acid (4-HPLA)). Metabolite concentrations were determined using a GC-2010 Plus gas chromatograph and a GCMS-QP2020 mass spectrometer (Shimadzu, Japan). The proportion of sepsis-associated aromatic metabolites in patients with sepsis was significantly higher than normal with a significance of 40%, while in donors, it did not exceed 5%. Comparison of the metabolomic profiles of normobiota and pathobiota in an experiment showed that when loaded with sepsis-associated metabolites of PLA and 4-HPLA, the microbiota of a healthy subject biotransforms them into the end products of microbial metabolism, whereas the pathobiota of a septic patient is unable to perform this function. Thus, in sepsis, the normobiome is transformed into a pathobiome, which reflects the dysfunction of the gut microbiota.