Risk Factors and Antimicrobial Resistance in Secondary Intracranial Infections Following Viral Encephalitis: A...

Secondary intracranial infections are common and severe complications in patients with viral encephalitis, contributing to higher mortality, prolonged hospitalization and increased healthcare burden. Evidence on risk factors, pathogen spectrum and resistance patterns remains limited, and predictive models tailored to this population are lacking.

We conducted a single-center retrospective cohort study, including 160 consecutive patients diagnosed with viral encephalitis. Clinical, therapeutic, laboratory and microbiological data were extracted from hospital records. Independent risk factors were identified using multivariate logistic and Cox regression. Predictive performance was assessed by receiver operating characteristic analysis. Pathogen distribution and antimicrobial resistance profiles were analyzed descriptively.

During a median follow-up of 16 days, 50 patients (31.3%) developed secondary intracranial infections, corresponding to an incidence of 2.9 events per 1000 patient-days. Independent predictors included older age (adjusted OR 1.39 per 10 years, P = 0.021), comorbidities (OR 2.18, P = 0.048), corticosteroid use ≥7 days (OR 2.45, P = 0.025), ≥2 invasive procedures (OR 2.92, P = 0.007) and elevated CSF protein (OR 2.36, P = 0.037). The multivariable risk score achieved an area under the curve of 0.86 (95% CI 0.80-0.92). Pathogen analysis revealed methicillin-resistant Staphylococcus aureus (MRSA) (24.0%) and Acinetobacter baumannii (20.0%) as predominant isolates, both showing high multidrug resistance, including carbapenem resistance rates of 70% in A. baumannii.

Secondary intracranial infections occur frequently in viral encephalitis and are strongly associated with host vulnerability. The predominance of MRSA and carbapenem-resistant A. baumannii underscores the urgent need for tailored infection control and antimicrobial strategies in neurocritical care.