Abstract: Objective To investigate the diagnosis and prognosis value of metagenomic Next-Generation Sequencing (mNGS) assay in patients with spontaneous bacterial peritonitis by comparing the results of mNGS and ascites culture from patients with liver cirrhosis. Methods Sixty inpatients diagnosed with cirrhosis and met the inclusion criteria were selected from our hospital between March 2021 and March 2023. Ascites specimens were collected using standardized operation, and both ascites culture and ascites mNGS assay were performed. The patients' general clinical data, etiology of cirrhosis, personal medical history, and antibiotic use were recorded. The scoring indexes used included APRI index, FIB-4 index, MELD score, MELD-Na score and Child-Pugh score. Results There was no significant difference in the patients' basic information and etiological composition of cirrhosis (P>0.05). The positive detection rate of ascitic fluid polymorphonuclear leukocyte counting method combined with ascitic fluid mNGS for SBP in cirrhosis was significantly higher than the detection method combined with ascitic fluid culture. The combined counting method and mNGS assay demonstrated a sensitivity of 86.67% and a specificity of 78.86%. Statistical results during the follow-up period revealed that the mNGS positive group had a higher incidence of adverse events, mortality rate, and liver cirrhosis related index scores. The mean MELD scores of the ascites mNGS positive group and the ascites mNGS negative group were 18.25 and 13.11, respectively. As for the mean MELD Na scores, the ascites mNGS positive group reported 23.82 ± 11.77, while the ascites mNGS negative group reported 14.58 ± 11.27. The MELD score and MELD-Na score for patients with mNGS positive ascites were significantly higher than those for patients with mNGS negative ascites. Moreover, the average Child Pugh scores for the two groups of patients were 11.25 and 9.75, respectively. The Child Pugh scores of patients with mNGS positive ascites were significantly higher than those of patients with mNGS negative ascites. Conclusion The combination of PMN count and mNGS was found to be more effective than ascites culture in guiding early treatment. Furthermore, a positive mNGS test was strongly associated with a poor prognosis in patients with cirrhotic SBP. These findings suggest that mNGS test can serve as improtant observational and predictive indicators of patient prognosis, making it a valuable tool for predicting adverse events during follow-up.

Key words: Cirrhosis, Spontaneous bacterial peritonitis, Ascites culture, mNGS test