Zoonotic bacterial meningitis in adults: clinical characteristics, etiology, treatment and outcome

In this thesis, we describe the clinical characteristics, etiology, treatment and outcome of zoonotic bacterial meningitis. Each chapter describes meningitis patients infected by a specific zoonotic pathogen, such as Streptococcus equi, Streptococcuis suis, Capnocytophaga canimorsus, Campylobacter fetus and Leptospira. We combine cases identified in a nationwide prospective cohort study of adult bacterial meningitis patients with a literature review on meningitis caused by each zoonotic pathogen.
Zoonotic pathogens are an uncommon cause of bacterial meningitis, but occur more frequently in individuals with specific risk factors, such as professional contact with pigs for Streptococcuis suis meningitis, and dog bites in alcoholic men for Capnocytophaga canimorsus meningitis. Zoonotic bacterial meningitis patients usually present with classic signs of meningitis including headache, fever and neck stiffness. However, CSF analysis often only shows a mildly elevated CSF leukocyte count, which may lead to confusion with viral meningitis. An immunocompromised state is associated with a worse prognosis in most pathogens causing zoonotic meningitis. Sequelae differ per pathogen, with hearing loss being the most frequent sequel, which mainly occurs in Streptococcus suis meningitis.
The thesis concludes with an overview of the clinical characteristics, etiology, treatment and outcome of zoonotic bacterial meningitis. We also added a description of rare zoonotic pathogens that were not identified in our cohort study, such as Bacillus anthracis and Francisella tularensis to the description of meningitis caused by the formerly mentioned zoonotic pathogens.