Case Report: Streptococcus suis-associated meningoencephalitis with profound bilateral labyrinthine deafness and intra-operative cochlear fibrosis treated by cochlear implantation.

Streptococcus suis is a common zoonotic pathogen that usually causes monomicrobial meningitis. Occult bloodstream detection of Klebsiella pneumoniae, together with proven central-nervous-system S. suis infection, followed by irreversible cochlear fibrotic changes requiring cochlear implantation, appears exceptionally rare. We report a 52-year-old male with chronic heavy alcohol intake and occupational swine-exposure history who developed severe sepsis, recurrent suppurative meningoencephalitis caused by S. suis, and permanent bilateral labyrinthine-related deafness. Combined blood and cerebrospinal fluid (CSF) metagenomic next-generation sequencing (mNGS) identified suspected additional bloodstream infection by K. pneumoniae, although K. pneumoniae was not detected in CSF. Multimodal antimicrobial, anti-inflammatory, and immunomodulatory therapy cleared intracranial infection but failed to restore hearing. Preoperative imaging suggested cochlear fibrotic changes; left-sided cochlear implantation achieved full electrode insertion with stable intraoperative neural responses despite abundant intracochlear fibrous tissue observed intraoperatively. This case raises three important considerations: occupational swine exposure together with chronic alcoholism may plausibly contribute to suspected polymicrobial sepsis; in selected patients, peripheral-blood mNGS may help identify occult Gram-negative bacteremia when CSF assays remain negative during recurrent meningitis; and cochlear fibrosis may not absolutely preclude technically-successful cochlear implantation.