What bacteria does meropenem cover?

Spectrum of Activity of Meropenem

Meropenem is a broad-spectrum carbapenem antibiotic effective against gram-positive, gram-negative, and anaerobic bacteria, including extended-spectrum beta-lactamase (ESBL)-producing pathogens and AmpC-producing organisms. 1

Gram-Positive Coverage

• Staphylococcus aureus (methicillin-susceptible isolates only) 1
• Streptococcus species:
  • Streptococcus pyogenes
  • Streptococcus agalactiae
  • Viridans group streptococci 1
  • Streptococcus pneumoniae (penicillin-susceptible isolates) 1
• Enterococcus faecalis (vancomycin-susceptible isolates only) 1
• Not effective against:
  • Methicillin-resistant Staphylococcus aureus (MRSA)
  • Enterococcus faecium 2

Gram-Negative Coverage

• Enterobacteriaceae:
  • Escherichia coli
  • Klebsiella pneumoniae
  • Proteus mirabilis 1
• Non-fermentative gram-negative bacilli:
  • Pseudomonas aeruginosa 3, 1
• Other gram-negatives:
  • Haemophilus influenzae
  • Neisseria meningitidis 1

Anaerobic Coverage

• Bacteroides fragilis
• Bacteroides thetaiotaomicron
• Peptostreptococcus species 1

Special Considerations

ESBL-Producing Organisms

Meropenem maintains activity against extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae and AmpC-producing organisms 4. For ESBL-producing organisms, carbapenems like meropenem are preferred over third-generation cephalosporins 3.

Pseudomonas Coverage

Meropenem belongs to Group 2 carbapenems (along with imipenem/cilastatin and doripenem) which have activity against non-fermentative gram-negative bacilli including Pseudomonas aeruginosa 3. When treating complicated skin and skin structure infections caused by P. aeruginosa, a higher dose of 1 gram every 8 hours is recommended 1.

Resistant Organisms

Meropenem is not effective against:

• Methicillin-resistant Staphylococcus aureus (MRSA)
• Enterococcus faecium
• Stenotrophomonas maltophilia 5
• Carbapenem-resistant Enterobacteriaceae (CRE)

Clinical Applications

Meropenem is indicated for:

1. Complicated skin and skin structure infections 1
2. Complicated intra-abdominal infections 1
3. Bacterial meningitis (pediatric patients ≥3 months) 1
4. Nosocomial pneumonia 3
5. Febrile neutropenia 6

Antimicrobial Stewardship Considerations

Due to concerns about emerging carbapenem resistance, the use of carbapenems should be limited to preserve activity of this class of antibiotics 3. When Pseudomonas coverage is not needed, consider using ertapenem instead of meropenem as part of antimicrobial stewardship 6.

Meropenem's broad spectrum makes it particularly valuable for empiric therapy of serious infections, but appropriate de-escalation based on culture results is essential to prevent development of resistance.