What is the first line treatment for streptococcal (Streptococcus) infections, specifically streptococcal pharyngitis?

First-Line Treatment for Streptococcal Pharyngitis

Penicillin V is the first-line treatment for streptococcal pharyngitis due to its narrow spectrum of activity, which minimizes disruption to normal flora and reduces the risk of developing antibiotic resistance. 1

Recommended Treatment Regimens

First-Line Options:

• Penicillin V (preferred):

  • Adults: 250 mg four times daily OR 500 mg twice daily for 10 days 1
  • Children: 250 mg two or three times daily for 10 days 1

• Amoxicillin (alternative first-line):

  • 50 mg/kg once daily (maximum 1000 mg) OR
  • 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1

Important Considerations for Penicillin V Use

• A full 10-day course is mandatory to eliminate the organism and prevent sequelae of streptococcal disease 1, 2
• Follow-up cultures should be obtained after treatment completion to confirm eradication 2
• The oral route should not be relied upon in patients with severe illness, nausea, vomiting, or intestinal hypermotility 2
• Patients should be counseled to complete the full course of therapy even if they feel better early in treatment 2

Alternative Treatments for Penicillin-Allergic Patients

• Azithromycin: 12 mg/kg once daily (max 500 mg) for 5 days 1, 3
• Clindamycin: 300-450 mg orally three times daily for 10 days 1
• Clarithromycin: Also effective as an alternative 4

Clinical Diagnosis and Testing

• Clinical diagnosis alone is insufficient; bacteriologic confirmation is required 1
• Use Centor Criteria to assess likelihood of Group A Streptococcus (GAS) pharyngitis 1
• Rapid Antigen Detection Tests (RADTs) should be considered for patients with high likelihood of streptococcal infections (3-4 Centor criteria) 1, 5

Cautions and Pitfalls

• Macrolide resistance: Some strains of GAS may be resistant to azithromycin; susceptibility testing should be performed when using this alternative 3
• Penicillin V limitations: Unlike azithromycin, penicillin V has no data establishing efficacy in preventing rheumatic fever 3
• Compliance concerns: The twice-daily regimen of penicillin V (500 mg BID) is as effective as the three-times-daily regimen and may improve compliance 6
• Gastrointestinal side effects: Adverse events, particularly gastrointestinal complaints, are more common with azithromycin (16.6%) than with penicillin (1.7%) 7

Prevention and Supportive Care

• Maintain isolation precautions for a minimum of 24 hours after starting effective antibiotic therapy 1
• Ensure adequate hydration during recovery 1
• Hand hygiene and avoiding close contact with infected individuals are important preventive measures 1

Special Populations

• For patients with severe illness or invasive Group A Streptococcal infections, the combination of penicillin G and clindamycin is recommended 1
• Testing or treatment of asymptomatic household contacts is not routinely recommended 1