Traceability of septic shock caused by phocaeicola vulgatus: a rare case report

Phocaeicola vulgatus (P.vulgatus) is a member of Bacteroides fragilis Group(BFG). Septic shock caused by P.vulgatus has not been reported yet. In recent years, BFG have attracted much clinical attention. BFG are the commensal microbiota residing in human mucosal sites, most notably the gut, that provide several benefits to healthy hosts. Yet BFG can cause devastating infections when they gain access to normally sterile body compartments following trauma, surgery, or mucosal barrier disruption.

We report a case of septic shock event in a middle-aged male who underwent surgical intervention for a gallbladder mass incidentally detected during routine abdominal CT screening. P.vulgatus was isolated and cultured from blood sample and abdominal drainage fluid after surgery. We further performed the Metagenomic Next-Generation Sequencing (mNGS) with pathological slices of colon and hepatobiliary tissue, and result of mNGS also showed P.vulgatus. The patient was treated with comprehensive therapies and had a good outcome.

To the best of our knowledge, septic shock secondary to P.vulgatus infection originating from non-gastrointestinal area represents an rare clinical condition. We realized that research on BFG should not only focus on its positive effects on the intestine, but also on its potential pathogenicity, including intra-abdominal infections, abscesses, and bloodstream infection.