What is the recommended treatment for a patient with a throat culture showing moderate growth of Group A Streptococcus?

Treatment of Group A Streptococcal Pharyngitis

Penicillin or amoxicillin for 10 days is the recommended first-line treatment for Group A Streptococcal pharyngitis, with penicillin remaining the drug of choice due to its proven efficacy, narrow spectrum, safety profile, and low cost. 1

First-Line Treatment Options

For Patients Without Penicillin Allergy

Oral Penicillin V is the preferred agent 1:

• Adults: 500 mg twice daily OR 250 mg three to four times daily for 10 days 1
• Children: 250 mg two to three times daily for 10 days 1, 2
• Twice-daily dosing is as effective as three or four times daily dosing and may improve compliance 3, 4, 5

Oral Amoxicillin is an acceptable alternative, particularly for young children due to better palatability 1:

• Once-daily dosing: 50 mg/kg (maximum 1000 mg) for 10 days 1, 2
• Twice-daily dosing: 25 mg/kg per dose (maximum 500 mg per dose) for 10 days 2
• Once-daily amoxicillin has been shown to be as effective as twice-daily dosing and conventional penicillin regimens 6, 7

Intramuscular Benzathine Penicillin G is recommended when adherence to oral therapy is questionable 1:

• Single dose: 600,000 units for patients <27 kg; 1.2 million units for patients ≥27 kg 1, 2

Critical Treatment Duration

The full 10-day course must be completed to achieve maximal pharyngeal eradication of Group A Streptococcus and prevent rheumatic fever, regardless of symptom resolution 1, 2, 8, 9

Treatment for Penicillin-Allergic Patients

Non-Anaphylactic Penicillin Allergy

First-generation cephalosporins (e.g., cephalexin, cefadroxil) for 10 days are preferred over broad-spectrum agents 1:

• Narrow-spectrum cephalosporins minimize selection of antibiotic-resistant flora 1
• Cephalosporins should NOT be used in patients with immediate (anaphylactic-type) hypersensitivity to penicillin, as up to 10% may also be allergic to cephalosporins 1

Immediate-Type Hypersensitivity to Penicillin

Clindamycin for 10 days 1:

• Resistance among Group A Streptococcus isolates in the United States is approximately 1% 1
• Appropriate for patients who cannot tolerate β-lactam antibiotics 1

Macrolides/Azalides for penicillin-allergic patients 1:

• Azithromycin: 12 mg/kg/day (maximum 500 mg) for 5 days 1, 2, 10
• Clarithromycin: 7.5 mg/kg twice daily (maximum 250 mg per dose) for 10 days 2
• Erythromycin: 10 days (associated with higher rates of gastrointestinal side effects) 1
• Important caveat: Macrolide resistance rates among pharyngeal isolates in most areas of the United States have been around 5-8%, with some studies suggesting clarithromycin for 10 days may be more effective than azithromycin for 5 days 1, 10

Agents NOT Recommended

The following should NOT be used for Group A Streptococcal pharyngitis 1:

• Tetracyclines: High prevalence of resistant strains 1
• Sulfonamides and trimethoprim-sulfamethoxazole: Do not eradicate Group A Streptococcus 1
• Older fluoroquinolones (e.g., ciprofloxacin): Limited activity against Group A Streptococcus 1
• Newer fluoroquinolones (e.g., levofloxacin, moxifloxacin): Unnecessarily broad spectrum and expensive 1

Short-Course Therapy Considerations

While the FDA has approved cefdinir, cefpodoxime, and azithromycin for 5-day courses, these shorter courses of oral cephalosporins cannot be endorsed due to concerns about study quality, broader spectrum, and higher cost compared to penicillin 1

Adjunctive Symptomatic Management

Analgesic/antipyretic agents are recommended for symptom relief 1, 2, 11:

• Acetaminophen or NSAIDs for moderate to severe symptoms or fever control 2, 11
• Aspirin should be avoided in children due to risk of Reye syndrome 2, 11
• Corticosteroids are NOT recommended for routine use 2, 11

Follow-Up and Monitoring

Routine post-treatment throat cultures or rapid antigen detection tests are NOT recommended for asymptomatic patients who have completed therapy 1, 2

Asymptomatic household contacts should NOT be routinely tested or treated unless there are special circumstances such as increased risk of frequent infections or nonsuppurative streptococcal sequelae 1

Management of Recurrent Episodes

For patients with a second episode of acute pharyngitis with positive culture shortly after completing therapy 1:

• Retreat with any appropriate first-line agent for a single recurrence 1
• Consider chronic carrier state if multiple episodes occur, as these patients may be experiencing viral infections rather than true recurrent bacterial infections 1
• For documented multiple recurrences, alternative regimens with higher eradication rates may be considered (see Table 5 in guidelines) 1

Common Pitfalls to Avoid

• Do not prescribe antibiotics without confirming diagnosis through throat culture or rapid antigen detection test 1
• Do not use broad-spectrum antibiotics when narrow-spectrum options are effective 1, 2
• Do not discontinue therapy early even if symptoms resolve, as the full 10-day course is essential to prevent rheumatic fever 1, 2, 8, 9
• Do not routinely test or treat asymptomatic contacts 1