How do you treat Group C/G streptococcal (Streptococcus) pharyngitis?

Treatment of Group C/G Streptococcal Pharyngitis

Yes, treat Group C/G streptococcal pharyngitis with penicillin or amoxicillin using the same regimen as Group A streptococcal pharyngitis—penicillin remains adequate under most circumstances for these infections. 1

Primary Treatment Approach

• Penicillin or amoxicillin is the first-line treatment for Group C/G streptococcal pharyngitis, following the same dosing and duration as for Group A streptococcus. 1

• A full 10-day course is essential to achieve maximal pharyngeal eradication and prevent potential complications, even though Group C/G streptococci are less commonly associated with rheumatic fever than Group A. 2, 3

• For adults: Penicillin V 250-500 mg orally 2-3 times daily for 10 days, or amoxicillin 500 mg twice daily for 10 days. 2

• For children: Amoxicillin 50 mg/kg/day divided twice daily (maximum 1000 mg/day) for 10 days provides equivalent efficacy with better palatability. 4

Penicillin-Allergic Patients

For non-immediate (non-anaphylactic) penicillin allergy:

• First-generation cephalosporins are the preferred alternative, with cephalexin 500 mg orally every 12 hours for adults (or 20 mg/kg per dose twice daily for children) for 10 days. 2

• Cross-reactivity risk is only 0.1% in patients with non-severe, delayed penicillin reactions. 2

For immediate/anaphylactic penicillin allergy:

• Clindamycin is the preferred choice: 300 mg orally three times daily for adults (or 7 mg/kg per dose three times daily for children, maximum 300 mg/dose) for 10 days. 2

• Clindamycin has approximately 1% resistance among streptococci in the United States and demonstrates high efficacy even in chronic carriers. 2

• Azithromycin is an acceptable alternative: 500 mg once daily for adults (or 12 mg/kg once daily for children, maximum 500 mg) for 5 days, but carries 5-8% macrolide resistance rates. 2

Critical Considerations Specific to Group C/G Streptococci

• Treatment failure can occur with penicillin in Group C/G infections, though penicillin remains adequate under most circumstances. 1

• Group C/G streptococci may be resistant to tetracyclines, macrolides, and clindamycin—consider local resistance patterns when selecting alternatives. 1

• These organisms are microbiologically similar to Group A streptococcus and cause similar throat and skin/soft tissue infections. 1

• Life-threatening invasive infections occur most frequently in patients with severe underlying medical diseases. 1

Common Pitfalls to Avoid

• Do not shorten the antibiotic course below 10 days (except for azithromycin's 5-day regimen), as this dramatically increases treatment failure rates. 2, 3

• Do not use cephalosporins in patients with immediate/anaphylactic penicillin reactions due to up to 10% cross-reactivity risk. 2

• Do not use trimethoprim-sulfamethoxazole, tetracyclines, or sulfonamides, as they fail to eradicate streptococci effectively. 4

• Do not assume compliance—in populations where follow-up is lacking or compliance cannot be assured, consider intramuscular benzathine penicillin G (1.2 million units IM once for adults, 600,000 units for children <27 kg). 5

Adjunctive Therapy

• Use acetaminophen or NSAIDs (such as ibuprofen) for moderate to severe symptoms or high fever. 2

• Avoid aspirin in children due to Reye syndrome risk. 2

• Corticosteroids are not recommended. 2