# Septic Shock Caused by Coinfection of Shewanella algae Bloodstream Infection and Epstein‐Barr Virus: Clinical Characteristics and Genomic Analysis

## TL;DR

A case of septic shock in inland China is caused by a coinfection of Shewanella algae and Epstein-Barr virus, with genomic analysis revealing freshwater adaptation and immune system impact.

## Contribution

The study reveals freshwater adaptation of Shewanella algae and the synergistic pathogenic role of EBV coinfection in causing septic shock.

## Key findings

- The S. algae strain showed freshwater adaptation through unique genes for transporters and carbohydrate enzymes.
- EBV coinfection accelerated septic shock via immunosuppression and inflammation.
- The patient succumbed to multi-organ failure from the coinfection.

## Abstract

Shewanella algae, a marine‐origin opportunistic pathogen, has shown a significant increase in non‐coastal infections, yet its environmental adaptability and synergistic pathogenic mechanisms with Epstein‐Barr virus (EBV) coinfection remain unclear. This study reports a clinical case of S. algae bloodstream infection complicated by EBV reactivation leading to septic shock in Sichuan Province, China, and elucidates the molecular mechanisms through genomic analysis. Pathogen identification was performed via blood culture, antibiotic susceptibility testing, and genomic annotation. The strain harbored resistance genes (acrB, tolC, tet(35), golS) and virulence factors (bplL/bplF, clpC/clpP, tonB). Phylogenetic analysis indicated the highest genetic affinity to freshwater‐derived Shewanella chilikensis, while pan‐genome analysis identified 1412 unique genes, including transmembrane transporters and carbohydrate‐active enzyme genes, suggesting freshwater adaptive evolution. Metagenomic next‐generation sequencing (mNGS) detected a high EBV load. The patient succumbed to multi‐organ failure. This study reveals that S. algae may evolve freshwater adaptability to cause inland infections, and EBV coinfection accelerates septic shock through immunosuppression and inflammatory cascades. Genomic analysis provides critical insights for precision diagnosis and treatment of polymicrobial infections.

This study reports a septic shock case in inland China caused by coinfection of Shewanella algae bloodstream infection and Epstein‐Barr virus. Genomic analysis revealed freshwater adaptation of the strain via unique genes for transporters and carbohydrate‐active enzymes. EBV coinfection accelerated septic shock through immunosuppression and inflammatory cascades.