Objective To understand the etiology, clinical prognosis and risk factors of adult community-acquired acute bacterial meningitis （ABM） and provide the evidence for clinical diagnosis and treatment. Methods We performed a retrospective study of 181 clinically diagnosed hospitalized patients with community-acquired adult ABM from Jan.2010 to Jan.2018. The patients were categorized as non-elderly (16≤age＜65 years old, n=156 ) and elderly (age≥65 years old, n=25) group. The etiology, clinical features, prognosis and risk factors of the two groups were compared. Results Sixty-four of 181 patients (35.4%) had pathogens detected. The most common pathogens were Streptococcus pneumoniae (17.9%), Listeria monocytogenes (13.4%) and Klebsiella pneumoniae (10.5%). The mortality of the elderly group was higher than that of the non-elderly group (P<0.05). Univariate analysis showed that there was a significant difference between the elderly group and the non-elderly group in the incidence of hypertension, hypokalemia, pulmonary infection, ear-nose-throat ( ENT) infection, cerebrospinal fluid (CSF) protein concentration, head CT abnormalities and mortality. Logistic regression analysis showed that pulmonary infection and temperature ≥38.5 ℃ were independent risk factors for poor prognosis in the non-elderly group. CSF pressure ≥200 mmH2O was a independent risk factors for poor prognosis in the elderly group. Conclusion The pathogens that cause acute bacterial meningitis in adult community are mainly Streptococcus pneumoniae, Listeria monocytogenes and Klebsiella pneumoniae.Pulmonary infection and temperature ≥38.5 ℃ are independent risk factors of poor prognosis in the non-elderly patients, as CSF pressure ≥200 mmH2O a independent risk factor in the elderly patients.
