What is the recommended antibiotic treatment for streptococcal (strep) infections?

Recommended Antibiotic Treatment for Streptococcal Infections

Penicillin V is the first-line treatment for streptococcal pharyngitis due to its proven efficacy, safety profile, narrow antimicrobial spectrum, and low cost. 1

First-Line Treatment

• Penicillin V:

  • Adults: 500 mg twice daily or 250 mg three times daily for 10 days
  • Children: 250 mg twice daily or 20 mg/kg/day divided every 8 hours for 10 days 1

• Amoxicillin (alternative first-line option):

  • 50 mg/kg once daily (maximum 1000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1
  • Once-daily dosing may improve compliance while maintaining efficacy 2

For Penicillin-Allergic Patients

Immediate-Type Hypersensitivity (anaphylaxis, angioedema, respiratory distress):

• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 3

  • Note: Azithromycin should not be relied upon to prevent rheumatic fever as data establishing efficacy in prevention are not available 3
  • Higher incidence of adverse events compared to amoxicillin 4

• Clarithromycin: 250 mg twice daily for 10 days 1

• Clindamycin:

  • Adults: 300-450 mg every 6 hours for more severe infections
  • Children: 8-20 mg/kg/day divided into three or four equal doses 1, 5
  • Must be taken with a full glass of water to avoid esophageal irritation 5
  • Risk of significant diarrhea (including C. difficile infection) 5

Non-Immediate Reactions:

• Cephalexin or other first-generation cephalosporins 1

Treatment Duration

• 10-day course is crucial for penicillin, amoxicillin, and most alternatives (except azithromycin) to:

  • Prevent acute rheumatic fever
  • Ensure complete eradication of Group A Streptococcus
  • Reduce risk of treatment failure 1

• For β-hemolytic streptococcal infections, treatment should continue for at least 10 days even with clindamycin 5

Clinical Decision-Making

1. Use Centor Criteria to guide testing and treatment decisions:

   • Tonsillar exudates
   • Tender anterior cervical lymph nodes
   • Lack of cough
   • Fever 1

2. Testing recommendations:

   • 0-2 Centor criteria: No testing or antibiotics needed
   • 3-4 Centor criteria: Test with rapid antigen detection test (RADT) and/or throat culture 1

3. Treatment challenges:

   • Penicillin treatment failure rates have increased to approximately 30% in recent decades, primarily due to non-compliance with the 10-day regimen 6
   • Cephalosporins may have better clinical outcomes in some cases, but evidence is of low certainty 4

Symptomatic Treatment

• NSAIDs or acetaminophen for pain and fever management
• Warm salt water gargles and throat lozenges to alleviate symptoms 1

Important Caveats

• Susceptibility testing should be performed when using azithromycin due to potential resistance 3
• Complete the full antibiotic course even if symptoms improve quickly
• Bacteriologic eradication rates may be lower with azithromycin (38%) compared to penicillin V (81%), despite similar clinical success rates 7
• For patients with history of rheumatic fever, continuous antimicrobial prophylaxis is recommended to prevent recurrences 1