Concurrent Detection of Streptococcus pneumoniae and Herpes Simplex Virus Type 1 (HSV-1) in Cerebrospinal Fluid: Clinical Interpretation Beyond Molecular Positivity.

Herpes simplex virus type 1 (HSV-1) encephalitis and acute bacterial meningitis are severe central nervous system infections associated with significant morbidity. While typically distinct, the increasing use of multiplex polymerase chain reaction (PCR) panels has led to occasional co-detection, creating diagnostic uncertainty. We describe a 44-year-old previously healthy male diagnosed with culture-confirmed pneumococcal meningitis in whom multiplex cerebrospinal fluid PCR also detected HSV-1. The clinical course was complicated by a generalized seizure on hospital day 3 and the development of ventriculitis on day 14, despite negative repeat microbiological assays. Following targeted antibacterial and antiviral therapy, the patient achieved complete neurological recovery. This case highlights the complexity of interpreting molecular results in the setting of severe blood-brain barrier disruption and emphasizes a cautious, chronologically driven approach to management.