Is Augmentin (amoxicillin-clavulanate) effective for treating Group B streptococcal (GBS) infections?

Effectiveness of Augmentin for Group B Streptococcal Infections

Augmentin (amoxicillin-clavulanate) is not recommended as a first-line treatment for Group B Streptococcal (GBS) infections, with penicillin G and ampicillin being the preferred agents according to CDC guidelines. 1

First-Line Treatment Options for GBS

For treatment of GBS infections, the CDC recommends:

• Penicillin G: 5 million units IV initial dose, then 2.5-3.0 million units IV every 4 hours until delivery (preferred due to narrow spectrum) 1
• Ampicillin: 2 g IV initial dose, then 1 g IV every 4 hours until delivery (alternative first-line) 1

Alternative Options for Penicillin-Allergic Patients

For patients with penicillin allergy, the treatment algorithm depends on the risk of anaphylaxis:

• Low risk for anaphylaxis: Cefazolin, 2 g IV initial dose, then 1 g IV every 8 hours until delivery 1
• High risk for anaphylaxis (history of anaphylaxis, angioedema, respiratory distress, or urticaria):
  • If GBS isolate is susceptible: Clindamycin, 900 mg IV every 8 hours until delivery
  • If susceptibility unknown or resistant: Vancomycin, 1 g IV every 12 hours until delivery 1

Role of Augmentin (Amoxicillin-Clavulanate)

While Augmentin has shown efficacy against GBS in certain settings:

• A 2015 study found that GBS isolates were highly susceptible to Augmentin 2
• However, Augmentin is not included in any of the major guidelines for GBS prophylaxis or treatment 1
• The addition of clavulanic acid primarily extends coverage to beta-lactamase producing organisms, which is unnecessary for GBS as it remains universally susceptible to penicillin 1

Clinical Considerations

• GBS remains universally susceptible to penicillin, making it the drug of choice due to its narrow spectrum 1
• Using broader-spectrum agents like Augmentin unnecessarily increases the risk of selecting for resistant organisms 1
• For GBS bacteriuria during pregnancy, appropriate treatment is essential as it represents heavy colonization 2

Special Situations

1. Neonatal GBS disease: Treatment should include ampicillin plus coverage for gram-negative pathogens 1

2. GBS endocarditis: European Society of Cardiology recommends penicillin G or ampicillin (sometimes with gentamicin) for susceptible streptococci, with no mention of Augmentin 1

Important Caveats

• Complete the full course of antibiotics even if symptoms improve quickly
• Intrapartum antibiotic prophylaxis has been shown to reduce vertical transmission of GBS by 86-89% 1
• Antenatal oral antibiotics alone are not effective for preventing early-onset GBS disease 1
• Chlorhexidine vaginal wipes or douches have not proven effective at preventing early-onset GBS disease 1

In conclusion, while Augmentin may be active against GBS, it offers no advantage over penicillin or ampicillin for GBS infections and introduces unnecessary broad-spectrum coverage. Penicillin remains the gold standard due to its narrow spectrum and excellent efficacy against GBS.