Clinical Features and Risk Factors of Group B Streptococcal Meningitis in Infants Younger than 4 Months: A 14-Year Experience at a University Hospital

Purpose: Group B Streptococcus (GBS) is a leading cause of invasive infections in infants. However, data on GBS meningitis in young infants remain limited. This study investigated the clinical features and risk factors of GBS meningitis in infants younger than 4 months.Methods: Medical records were retrospectively reviewed at a university hospital over a 14-year period from 2009 to 2022. Fifty cases of invasive GBS infection were identified among 32,851 young infants. Patients were divided into a meningitis group (group M; n=20) and a sepsis without meningitis group (group S; n=30).Results: The proportion of outborn patients (i.e., those born outside the authors’ hospital) was higher in group M than in group S (75% vs. 43%). The proportion of patients with late-onset disease, defined as onset ≥7 days after birth, was also higher in group M than in group S (85% vs. 57%). Among early clinical symptoms and laboratory findings, only an elevated C-reactive protein (CRP) level was associated with meningitis (odds ratio, 14; 95% confidence interval, 1.1 to 183.8). Hospital outcomes, including 30-day mortality, did not differ between the groups. Most patients with GBS meningitis had abnormal brain imaging findings.Conclusion: GBS meningitis was more common among outborn infants than in those born at the authors’ hospital and frequently developed as late-onset disease. An elevated CRP level in the early stage of infection was associated with the development of meningitis.