What is the recommended treatment for a patient with an indeterminate strep throat PCR (Polymerase Chain Reaction) for group C/G and no detection of strep A?

Management of Indeterminate Strep Throat PCR for Group C/G with Negative Strep A

For patients with indeterminate PCR results for group C/G streptococci and negative Strep A testing, watchful waiting without antibiotics is recommended as the primary approach, as these findings do not warrant empiric antibiotic therapy in the absence of severe symptoms or high-risk factors.

Diagnostic Interpretation

When faced with indeterminate PCR results for group C/G streptococci and negative Strep A:

• This result pattern indicates:

  • No evidence of Group A Streptococcus (GAS) infection
  • Inconclusive evidence regarding Groups C/G streptococci
  • Likely viral etiology for the pharyngitis

• Clinical context is crucial:

  • The Infectious Diseases Society of America emphasizes that clinical diagnosis of streptococcal pharyngitis cannot be made with certainty even by experienced physicians 1
  • The Centor Criteria should be used to assess likelihood of streptococcal infection 1

Management Approach

Primary Recommendation

1. Watchful waiting is appropriate for most patients with:

   • Negative Strep A test
   • Indeterminate Group C/G results
   • Mild to moderate symptoms

2. Supportive care:

   • Maintain hydration (crucial for recovery) 1
   • Consider analgesics for symptom relief
   • Rest until symptoms improve

When to Consider Antibiotics

Antibiotics may be considered if:

• Patient has ≥3 Centor criteria (fever, tonsillar exudate, tender cervical lymphadenopathy, absence of cough) AND
• High clinical suspicion despite negative Strep A test OR
• Patient is at high risk for complications (history of rheumatic fever, immunocompromised)

If antibiotics are deemed necessary:

• First-line: Penicillin V (250 mg four times daily or 500 mg twice daily for adults) for 10 days 1
• Alternative: Amoxicillin (50 mg/kg once daily, maximum 1000 mg) for 10 days 1
• For penicillin-allergic patients: Clindamycin, azithromycin, or clarithromycin 1

Important Considerations

Group C/G Streptococci

• Unlike Group A strep, Groups C/G:
  • Are not strongly associated with acute rheumatic fever
  • May cause pharyngitis but with less severe consequences
  • Often represent colonization rather than true infection

Follow-up Recommendations

• Follow-up throat cultures are not routinely recommended 1
• Exceptions where follow-up is warranted:
  • History of rheumatic fever
  • During outbreaks of acute rheumatic fever or post-streptococcal glomerulonephritis
  • Outbreaks in closed communities 1

Common Pitfalls to Avoid

1. Overtreatment: Avoid prescribing antibiotics for likely viral pharyngitis or colonization

   • Strep pharyngitis is usually self-limited, with fever and constitutional symptoms typically resolving within 3-4 days even without treatment 1

2. Misinterpreting indeterminate results: An indeterminate PCR for Groups C/G with negative Strep A does not warrant the same treatment approach as confirmed Strep A pharyngitis

3. Inadequate patient education: Ensure patients understand:

   • The self-limiting nature of most pharyngitis cases
   • When to return if symptoms worsen
   • The importance of hydration and rest

By following this evidence-based approach, unnecessary antibiotic use can be avoided while ensuring appropriate management of patients with indeterminate strep throat PCR results.