Microbiology and long-term outcomes in community-acquired, nosocomial and post-neurosurgical meningitis with positive bacterial culture in Ontario, Canada: A population-based cohort study

Background — Bacterial meningitis is a rare but severe infection that has a high risk of mortality and morbidity. The study objective was to describe the microbiology, long-term mortality risk, and complications from neurologic sequelae for bacterial meningitis.

Methods — This retrospective cohort study included adults with a positive cerebrospinal fluid (CSF) bacterial culture collected from 2014 to 2022 inclusive in Ontario, Canada. Patients were followed for 1 year. The primary outcome was all-cause mortality. Secondary outcomes included aspiration, enteral feeding tube insertion, decubitus ulcers, falls and/or fractures, and long-term care admissions.

Results — 856(2.1%) patients had positive CSF cultures including 431(50.4%) community-acquired, 255(29.8%) nosocomial and 170(19.9%) post-neurosurgical meningitis cases. Staphylococcus aureus was the second most common pathogen in community-acquired meningitis(10.9%) and the most common pathogen in nosocomial(11.8%) and post-neurosurgical(22.9%) meningitis. All-cause mortality at 30, 90, 180, and 365 days were 11.4%, 13.2%, 14.8% and 16.5% for community-acquired meningitis; 16.5%, 22.4%, 25.1% and 27.1% for nosocomial meningitis; and 10.6%, 20.0%, 25.9% and 28.8% for post-neurosurgical meningitis. Enteral feeding tube was inserted in 2.8%, 15.3%, and 20.0% of community-acquired, nosocomial, and post-neurosurgical meningitis cases respectively. Other secondary outcomes occurred rarely.

Conclusion — S. aureus was an important pathogen. Meningitis mortality continued to increase over 1 year. For nosocomial and post-neurosurgical meningitis, one in four died by 1 year and many required enteral feeding tube.