Hospital-based study of the distribution of pathogens in adult bacterial meningitis with underlying disease in Tokyo, Japan

Background and Aim: Therapeutic management of bacterial meningitis worldwide has been established based on the patient age and risk factors. Aim: The present study investigated the distribution of pathogens and outcomes in adult bacterial meningitis with underlying disease in Tokyo, Japan. Methods: Participants in this retrospective study were 131 adult cases diagnosed with having bacterial meningitis based on their clinical symptoms and laboratory data. All patients had been admitted to our hospitals (Nihon University Itabashi Hospital and Surugadai Hospital) in Tokyo, Japan, between 1984 and 2013. Bacterial meningitis was classified with underlying disease into three groups, as follows: group 1, invasive procedures or complicated head trauma within the preceding 3 months (n = 35); group 2, immunocompromised status (n = 37); or group 3, both conditions (n = 31). Poor outcome was defined as a Glasgow Outcome Scale score of 1–3. Results: The distribution of pathogens differed significantly in each group. The most common pathogen in each group was Staphylococcus epidermidis (23.7%) in group 1; penicillin-intermediate Streptococcus pneumoniae (12.8%) in group 2; and Staphylococcus epidermidis (13.9%) in group 3. The highest rate of mortality and poor outcome was shown in group 2, and followed by group 3 and 1. The rate of antibiotic-resistant bacteria was 68.9% for all pathogens in bacterial meningitis with underlying disease, 70.6% in group 1, 55.6% in group 2 and 80.6% in group 3. Conclusion: This is the first retrospective study of the distribution of pathogens and outcomes in adult bacterial meningitis with underlying disease in Japan.