What is the appropriate treatment for a patient with a strep culture showing beta-hemolytic streptococci, not group A?

Management of Beta-Hemolytic Streptococci (Non-Group A)

Do not treat beta-hemolytic streptococci that are not confirmed to be Group A streptococcus, as only Group A streptococcus causes the complications (acute rheumatic fever, suppurative complications) that justify antibiotic therapy. 1

Critical Distinction: Beta-Hemolytic Does Not Equal Group A

The presence of beta-hemolytic colonies on culture is insufficient for treatment because multiple beta-hemolytic streptococci exist beyond Group A, including:

• Group B streptococci (Streptococcus agalactiae)
• Group C streptococci
• Group G streptococci 1, 2

These non-Group A beta-hemolytic streptococci have different clinical significance and do not cause acute rheumatic fever or the suppurative complications that are the primary justification for antibiotic treatment in pharyngitis. 1

Required Laboratory Confirmation

Proper identification requires specific grouping through:

• Latex agglutination testing for Group A carbohydrate antigen
• Immunofluorescence
• Definitive serological grouping methods 1

Group A streptococci are beta-hemolytic, but not all beta-hemolytic streptococci are Group A—this is the critical laboratory distinction that must be made before initiating therapy. 1

Treatment Algorithm

If Group A Streptococcus is NOT Confirmed:

• Discontinue antibiotics if already started empirically 1
• The CDC advises against initiating antibiotics until Group A streptococcus is specifically confirmed, as empiric treatment of non-GAS pharyngitis leads to unnecessary antibiotic exposure, adverse effects, and antimicrobial resistance without preventing any complications 1
• Do not perform routine testing or treatment of asymptomatic household contacts 3

If Group A Streptococcus IS Confirmed:

• Penicillin V 500 mg orally twice daily for 10 days remains the treatment of choice 3, 1
• Intramuscular benzathine penicillin G is preferred for patients unlikely to complete oral therapy 3
• For penicillin-allergic patients (non-anaphylactic): first-generation cephalosporins 3
• For anaphylactic penicillin allergy: azithromycin 12 mg/kg once daily (maximum 500 mg) for 5 days, though macrolides should be avoided in areas with high resistance rates 1

Common Pitfalls to Avoid

The most critical error is treating beta-hemolytic colonies without confirming Group A status. This leads to:

• Unnecessary antibiotic exposure without clinical benefit 1
• Increased antimicrobial resistance 1
• Potential adverse drug effects 3
• No prevention of complications, as non-Group A beta-hemolytic streptococci do not cause acute rheumatic fever 1

Clinical diagnosis alone has insufficient accuracy (≤80% predictive value even with scoring systems), making microbiologic confirmation with specific Group A identification essential before initiating antibiotics. 1

When to Consider Treatment Despite Non-Group A Result

The IDSA recommends antimicrobial therapy may be initiated while laboratory confirmation is pending in cases of high clinical suspicion, provided therapy is discontinued if Group A streptococcus is not confirmed. 1 However, this should be the exception rather than the rule, reserved for patients with:

• Severe clinical presentation
• High risk for complications
• Inability to follow up for culture results 1