What is the initial empiric antibiotic regimen for suspected bacterial meningitis in adults?

• A. Vancomycin plus a third-generation cephalosporin (e.g., ceftriaxone) with dexamethasone
• B. Ceftriaxone alone
• C. Vancomycin alone
• D. Ampicillin plus gentamicin

Answer: (A)

Starting empiric therapy for suspected adult bacterial meningitis requires broad coverage of the most likely pathogens and resistance patterns, plus an anti-inflammatory measure to lessen brain injury from inflammation. Vancomycin targets penicillin‑resistant Streptococcus pneumoniae, while a third‑generation cephalosporin (such as ceftriaxone or cefotaxime) covers Neisseria meningitidis, Haemophilus influenzae, and many pneumococcal strains. Adding dexamethasone given just before or with the first antibiotic dose helps reduce inflammatory damage in the subarachnoid space and lowers the risk of neurologic complications, especially in pneumococcal meningitis. In patients over age 50 or those immunocompromised, ampicillin is typically added to cover Listeria monocytogenes, but the described regimen of vancomycin plus a third‑generation cephalosporin with dexamethasone represents the standard initial empiric approach in adults.