For a neonate (<28 days) with suspected meningitis the common empiric regimen is:

• IV Ampicillin 50 mg/kg/dose (to cover Group B strep and Listeria) plus
• An aminoglycoside (typically Gentamicin 2.5–4 mg/kg/dose IV) for Gram-negative coverage

Additionally, if there is any concern for herpes simplex virus (HSV) infection (e.g., maternal HSV history, seizures, skin lesions, or CSF pleocytosis), add:
• Acyclovir 20 mg/kg/dose IV

This approach is supported by pediatric guidelines that stratify neonatal meningitis treatment based on age (with <14 days sometimes using Gentamicin or an alternative cephalosporin in certain settings) and by recommendations emphasizing early coverage for HSV when indicated ¹².