Microbiota of ascitic fluid and other biotopes in liver cirrhosis: a pilot study

Objective. To determine the composition of the microbiota of ascitic fluid in patients with liver cirrhosis and compare it with the intestinal microbiota and urobiota. Materials and methods . A cross-sectional single-center study was conducted for 5 hospitalized patients with decompensated liver cirrhosis with ascites who, along with standard research methods, underwent metagenomic sequencing of ascitic fluid, urine and feces. High-throughput sequencing was performed using a MiSeq genetic analyzer (Illumina, USA) using a protocol based on the analysis of variable regions of the 16s rRNA gene. The assignment of taxonomic levels and quantitative assessment of the microbiome composition were performed using the Kraken 2 program (PlusPF database dated 06/05/2024). The study is registered in Clinicaltrials.gov (NCT05335213). Results . A unique composition of the ascitic fluid microbiota represented by 29 types, 35 classes, 67 orders, 129 families, 231 genera, and 266 bacterial species has been determined in patients with liver cirrhosis with ascites in the absence of spontaneous bacterial peritonitis. The Pseudomonadota is the dominant type (95,4% [94,8; 95,9]), the Gammaproteobacteria is the dominant class (47,7% [45,9; 48,4]), the Stenotrophomonas is the dominant genera (47,6% [46,2; 48,0]) in the microbiota of ascitic fluid. For the first time it has been shown that the similarity of the microbiota of ascitic fluid and urobiota is 68,3%, microbiota of ascitic fluid and gut – 69,0% at the type level. Conclusion . The study examined the microbiota of ascitic fluid in patients with liver cirrhosis using metagenomic sequencing. Despite the negative results of cultural research methods, it has been shown that ascitic fluid is not a sterile medium and contains a large number of microorganisms, which in most cases have commonalities with the microbiota of the gut and urinary tract.