What is the spectrum of activity of Meropenem (generic name)?

Meropenem Spectrum of Activity

Meropenem is a broad-spectrum carbapenem antibiotic with potent activity against gram-positive, gram-negative, and anaerobic bacteria, including extended-spectrum beta-lactamase (ESBL) and AmpC-producing Enterobacteriaceae, making it an important option for serious bacterial infections. 1

Gram-Positive Coverage

• Susceptible organisms include:

  • Staphylococcus aureus (methicillin-susceptible isolates only)
  • Streptococcus pneumoniae (penicillin-susceptible isolates only)
  • Streptococcus pyogenes
  • Streptococcus agalactiae
  • Viridans group streptococci
  • Enterococcus faecalis (vancomycin-susceptible isolates only) 2

• Important limitations:

  • No activity against methicillin-resistant Staphylococcus aureus (MRSA)
  • No activity against methicillin-resistant Staphylococcus epidermidis (MRSE) 2

Gram-Negative Coverage

• Highly active against:

  • Escherichia coli
  • Klebsiella pneumoniae
  • Pseudomonas aeruginosa
  • Haemophilus influenzae
  • Neisseria meningitidis
  • Proteus mirabilis 2

• Additional gram-negative coverage:

  • Aeromonas hydrophila
  • Citrobacter freundii
  • Citrobacter koseri
  • Enterobacter cloacae
  • Klebsiella oxytoca
  • Morganella morganii
  • Serratia marcescens
  • Moraxella catarrhalis 2

Anaerobic Coverage

• Active against:
  • Bacteroides fragilis
  • Bacteroides thetaiotaomicron
  • Peptostreptococcus species
  • Clostridium species (including C. difficile)
  • Prevotella species 2

Key Clinical Applications

1. Intra-abdominal infections:

   • Meropenem offers anti-anaerobic coverage, eliminating the need for additional metronidazole 3
   • Recommended for high-severity infections and healthcare-associated infections 3

2. Bacterial meningitis:

   • Alternative to third-generation cephalosporins with similar clinical and microbiologic outcomes 3
   • Lower seizure risk compared to imipenem, making it suitable for CNS infections 3, 4

3. Complicated urinary tract infections:

   • Particularly for ESBL-producing organisms and carbapenem-resistant Enterobacteriaceae (when combined with vaborbactam) 5

4. Other approved indications:

   • Complicated skin and skin structure infections
   • Nosocomial pneumonia
   • Septicemia
   • Febrile neutropenia 1

Resistance Considerations

• Mechanisms of resistance include:

  1. Decreased outer membrane permeability in gram-negative bacteria
  2. Reduced affinity of target penicillin-binding proteins
  3. Increased expression of efflux pump components
  4. Production of carbapenemases and metallo-β-lactamases 2

• Clinical implications:

  • In settings with high resistance rates, carbapenem-sparing strategies are recommended 3
  • Meropenem-vaborbactam combination maintains activity against KPC-producing organisms but not against OXA-48 producers 3

Synergistic Potential

• In vitro studies show meropenem acts synergistically with aminoglycosides against some Pseudomonas aeruginosa isolates 2

Safety Profile

• Well-tolerated with low incidence of adverse events (all <3%)
• Most common adverse events: diarrhea (2.5%), rash (1.4%), and nausea/vomiting (1.2%)
• Lower incidence of seizures compared to imipenem, with drug-related seizure incidence of only 0.07% in non-meningitis infections 4

Meropenem's broad spectrum of activity, favorable safety profile, and stability against many beta-lactamases make it an important antimicrobial agent for serious infections, particularly when resistance to other antibiotics is a concern or when treating polymicrobial infections.