What is the recommended treatment for moderate growth beta-hemolytic strep (Streptococcus) group C?

Treatment of Moderate Growth Beta-Hemolytic Streptococcus Group C

Penicillin is the first-line treatment for moderate growth beta-hemolytic Streptococcus group C, administered as oral penicillin V for 10 days or as intramuscular benzathine penicillin G for patients unlikely to complete oral therapy. 1

First-Line Treatment Options

• Oral penicillin V: For children, 250 mg two or three times daily; for adolescents and adults, 250 mg four times daily or 500 mg twice daily for 10 days 1, 2
• Amoxicillin: 50 mg/kg once daily (maximum 1,000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1, 3
• Intramuscular benzathine penicillin G: Single dose - <60 lb (27 kg): 600,000 units; ≥60 lb: 1,200,000 units 1, 2

Alternative Treatment for Penicillin-Allergic Patients

• For non-anaphylactic penicillin allergy:

  • Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg per dose) for 10 days 1
  • Cefadroxil: 30 mg/kg once daily (maximum 1 g) for 10 days 1

• For patients with immediate hypersensitivity to penicillin:

  • Clindamycin: 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days 1, 4
  • Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1
  • Clarithromycin: 7.5 mg/kg per dose twice daily (maximum 250 mg per dose) for 10 days 1

Clinical Considerations

• Although most guidelines focus on Group A streptococcal infections, the treatment approach for Group C streptococci follows similar principles 5
• Group C streptococci remain highly susceptible to penicillin, with very low resistance rates 6
• For serious Group C infections (bacteremia, meningitis, etc.), combination therapy with penicillin plus an aminoglycoside may be considered 5
• Treatment should continue for a full 10 days to ensure complete eradication of the organism, even if symptoms resolve earlier 1, 7

Potential Pitfalls and Caveats

• Macrolide resistance has been reported in Group C streptococci (5.8% resistance to erythromycin), so these agents should be used with caution in penicillin-allergic patients 6
• Treatment failures with penicillin have been reported in 6-25% of cases, potentially due to:
  • Poor adherence to the full 10-day regimen 8
  • Presence of beta-lactamase-producing organisms in the pharynx that may inactivate penicillin 9
• Follow-up testing after treatment is not routinely recommended unless symptoms persist 1
• For recurrent infections, consider clindamycin or amoxicillin/clavulanate as they have shown higher rates of pharyngeal eradication 1

Special Populations

• For immunocompromised patients or those with severe infections, consider hospitalization and intravenous therapy 5
• In patients with chronic cardiopulmonary disease, diabetes, malignancy, or alcoholism who have Group C streptococcal infections, more aggressive treatment and monitoring may be warranted due to higher risk of complications 5