Does meropenem cover Haemophilus influenzae and Streptococcus pyogenes?

Meropenem Coverage of Haemophilus influenzae and Streptococcus pyogenes

Yes, meropenem provides excellent coverage for both Haemophilus influenzae and Streptococcus pyogenes, with FDA-approved indications for H. influenzae meningitis and S. pyogenes skin/soft tissue infections. 1

FDA-Approved Coverage

Meropenem is FDA-approved for treating infections caused by both organisms:

• Haemophilus influenzae: Specifically indicated for bacterial meningitis in pediatric patients ≥3 months of age 1
• Streptococcus pyogenes: Indicated for complicated skin and skin structure infections in adults and pediatric patients ≥3 months 1

Microbiological Activity

The in vitro activity against both pathogens is robust:

• H. influenzae: Meropenem demonstrates MICs of 0.002-0.5 mg/L, with activity 4-64 times greater than imipenem against this organism 2, 3, 4
• S. pyogenes: Covered as part of beta-hemolytic streptococci, with MICs consistently in the 0.002-0.5 mg/L range 5

Clinical Guideline Support

Major society guidelines recognize meropenem's coverage of these pathogens:

• The American Thoracic Society/IDSA guidelines list meropenem as an antipseudomonal β-lactam that is "generally active against DRSP and other likely pathogens" including H. influenzae in severe community-acquired pneumonia 6
• IDSA skin/soft tissue infection guidelines include meropenem in treatment regimens for necrotizing infections where S. pyogenes is a key pathogen 6
• The IDSA meningitis guidelines recommend meropenem as an alternative therapy for H. influenzae meningitis 6

Important Clinical Considerations

While coverage is excellent, meropenem should be reserved for specific situations:

• Not first-line: Despite excellent activity, meropenem is a broad-spectrum agent that should be reserved rather than used routinely to prevent resistance development 7
• Preferred scenarios: Use when there are concerns about resistant pathogens, polymicrobial infections, or in critically ill patients requiring empiric broad-spectrum coverage 6, 7
• β-lactamase stability: Meropenem remains active against β-lactamase-producing H. influenzae strains that are ampicillin-resistant 3, 4

Dosing for These Pathogens

Standard dosing provides adequate coverage:

• Adults: 500 mg IV every 8 hours for skin/soft tissue infections; 1 gram IV every 8 hours for severe infections 1
• Pediatric meningitis (H. influenzae): 40 mg/kg IV every 8 hours (maximum 2 grams every 8 hours) 1
• Pediatric skin infections (S. pyogenes): 10 mg/kg IV every 8 hours 1