# From dysbiosis to prediction: a novel gut microbiota–derived index for spontaneous bacterial peritonitis in HBV-related cirrhosis

## TL;DR

This study identifies a gut microbiota-based index and prediction model for spontaneous bacterial peritonitis in patients with hepatitis B-related cirrhosis.

## Contribution

The novel SBP-MI index and SBP-RP model integrate microbial and clinical data to predict SBP risk in HBV-related cirrhosis.

## Key findings

- SBP is marked by pathogenic taxa enrichment and reduced short-chain fatty acid producers.
- The SBP-MI index tracks microbial changes and outperforms existing dysbiosis indices.
- The SBP-RP model achieves high predictive accuracy with an AUC of 0.91 for SBP risk.

## Abstract

Spontaneous bacterial peritonitis (SBP) is a severe complication of hepatitis B virus (HBV)-related cirrhosis, in which gut microbiota dysbiosis plays a pivotal role. This study aimed to characterize microbial alterations, establish a microbiota-derived index (SBP-MI), evaluate longitudinal changes, and develop an SBP risk prediction model (SBP-RP).

A total of 135 participants were included: healthy controls (n=40), compensated cirrhosis (n=30), cirrhosis with ascites but without SBP (n=40), and SBP (n=25). Fecal 16S rRNA sequencing and clinical data were obtained. An additional 140 cirrhotic patients with ascites were prospectively followed for 6 months, with SBP occurrence as the endpoint; 40 provided paired fecal samples. SBP-MI was constructed from key microbial shifts, and multivariable Firth logistic regression identified independent predictors.

SBP was characterized by enrichment of pathogenic taxa (Escherichia–Shigella, Klebsiella, Veillonella, Streptococcus) and depletion of short-chain fatty acid producers (Prevotella, Roseburia, Faecalibacterium, Bacteroides), forming the basis of SBP-MI. During follow-up, improved patients had greater microbial diversity and beneficial commensals, whereas progression was linked to Haemophilus expansion. SBP-MI effectively tracked these changes and outperformed the Hepatitis B Cirrhosis Dysbiosis Index. Multivariable analysis identified INR, previous history of SBP, and SBP-MI as independent predictors. The SBP-RP yielded an AUC of 0.91(95% CI: 0.82–0.99), with calibration that appeared acceptable in this cohort.

Distinct dysbiosis characterizes SBP. SBP-MI captures microbial imbalance and progression, while the SBP-RP model integrating microbial and clinical factors provides promising predictive value for early risk stratification.

Scientific infographic illustrates differences between healthy controls and SBP patients, showing gut microbiota composition and functions, barrier integrity, and outcomes. Includes ROC curves for endpoints in HBV-related cirrhosis patients over six months, comparing improved versus progression groups and SBP occurrence.