From the FDA Drug Label
Serious infections, such as pneumonia and endocarditis, due to susceptible strains of streptococci (including S pneumoniae) and meningococcus 150,000 - 300,000 units/kg/day divided in equal doses every 4 to 6 hours; duration depends on infecting organism and type of infection Penicillin G is highly active in vitro against streptococci (groups A, B, C, G, H, L, and M)
The recommended treatment for group B strep (Streptococcus agalactiae) bacteremia is penicillin G (IV) at a dosage of 150,000 - 300,000 units/kg/day divided in equal doses every 4 to 6 hours. The duration of treatment depends on the type of infection and the infecting organism 1. Penicillin G is highly active in vitro against streptococci (groups A, B, C, G, H, L, and M), making it an effective choice for treating group B strep bacteremia 1.
From the Research
The recommended treatment for Group B Streptococcus (GBS) bacteremia is intravenous penicillin G at a dose of 4 million units every 4 hours for at least 10-14 days. For patients with penicillin allergy, alternatives include ceftriaxone 2g IV daily, or in cases of severe beta-lactam allergy, vancomycin 15-20 mg/kg IV every 8-12 hours 2. Susceptibility testing should be performed to guide therapy, especially in serious infections.
Key Considerations
- For complicated bacteremia or if endocarditis is suspected, longer treatment courses of 4-6 weeks may be necessary.
- Addition of gentamicin (1 mg/kg every 8 hours) for synergy may be considered in severe infections like endocarditis, though this is controversial.
- Source control is essential, requiring removal of infected catheters or drainage of abscesses when present.
- GBS remains universally susceptible to penicillin, which is why it remains the first-line therapy, as supported by recent reviews on antibiotic resistance in GBS 3.
- The bactericidal activity of penicillin against the cell wall of this gram-positive organism makes it highly effective in clearing the infection from the bloodstream.
Special Considerations
- In neonates, ampicillin dosing recommendations have been updated, with specific guidelines for bacteremia and meningitis, although the evidence for meningitis dosing is limited 4.
- For pregnant women with a history of penicillin allergy, skin testing is now recommended to confirm or delabel the allergy, allowing for more appropriate prophylaxis during delivery 2.