Organism		Antibiotic (total daily dosage)
Unknown (suspected diagnosis)*		Cefotaxime, 8 to 12 g, or ceftriaxone, 4 g, plus ampicillin, 12 g
Streptococcus pneumoniae
	MIC: ≤ 0.1 μg per mL	Penicillin G, 20 to 24 million units
	MIC: 0.1 to 1.0 μg per mL	Cefotaxime, 8 to 12 g, or ceftriaxone, 4 g
	MIC: ≥ 1.0 μg per mL	Vancomycin, 2 g, plus ceftriaxone, 4 g
Listeria monocytogenes		Ampicillin, 12 g, plus an aminoglycoside: gentamicin, tobramycin, 3 to 5 mg per kg
Neisseria meningitides		Penicillin G, 20 to 24 million units, or ampicillin, 12 g
Haemophilus influenzae		Cefotaxime, 8 to 12 g, or ceftriaxone, 4 g
Enterobacteriaceae (gram-negative bacilli)		Cefotaxime, 8 to 12 g, or ceftriaxone, 4 g†