Bacteria Susceptible to Meropenem
Meropenem is effective against a broad spectrum of gram-positive, gram-negative, and anaerobic bacteria, including extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, Pseudomonas aeruginosa, and many multidrug-resistant organisms. 1
Gram-Negative Bacteria
Enterobacteriaceae
- Escherichia coli (100% susceptibility) 2
- Klebsiella pneumoniae (including many carbapenem-susceptible strains) 3, 4
- Proteus mirabilis 1
- Enterobacter species 5
- Citrobacter species 5
- Serratia marcescens 6
Non-Fermentative Gram-Negative Bacilli
- Pseudomonas aeruginosa (84-94% susceptibility) 2
- Note: Meropenem displays lower MICs against P. aeruginosa compared to imipenem 2
- Acinetobacter species (with varying susceptibility) 2, 4
- Haemophilus influenzae (including in meningitis) 1, 7
Other Gram-Negative Bacteria
- Neisseria meningitidis (in bacterial meningitis) 1
Gram-Positive Bacteria
Cocci
- Staphylococcus aureus (methicillin-susceptible isolates only) 1
- Streptococcus pneumoniae (penicillin-susceptible isolates in meningitis; for penicillin-resistant strains, MICs are higher but many remain susceptible) 1, 7
- Streptococcus pyogenes (Group A streptococci) 1
- Streptococcus agalactiae (Group B streptococci) 1
- Viridans group streptococci 1
- Enterococcus faecalis (vancomycin-susceptible isolates only) 1
Important Limitations
- Not effective against:
- Methicillin-resistant Staphylococcus aureus (MRSA)
- Enterococcus faecium
- Carbapenemase-producing organisms (e.g., KPC, NDM, OXA-48) 5
Anaerobic Bacteria
- Bacteroides fragilis 1
- Bacteroides thetaiotaomicron 1
- Peptostreptococcus species 1
- Clostridium difficile (MIC90 of 1.0 mg/L) 4
- Clostridium perfringens and other Clostridium species 4
Clinical Applications
Meropenem is FDA-approved for:
- Complicated skin and skin structure infections 1
- Complicated intra-abdominal infections (appendicitis, peritonitis) 1
- Bacterial meningitis (pediatric patients ≥3 months) 1
In many countries, it's also approved for:
- Nosocomial pneumonia
- Septicemia
- Febrile neutropenia
- Complicated urinary tract infections
- Severe community-acquired pneumonia 8
Important Clinical Considerations
- Dosing adjustment is required in patients with renal impairment (CrCl ≤50 mL/min) 1
- For carbapenem-resistant organisms, combination therapy (e.g., with colistin) may be necessary 6
- Carbapenem-resistant P. aeruginosa infections have increasing prevalence, with rates of meropenem non-susceptibility around 27.1% in pneumonia isolates 6
- Meropenem has a lower seizure potential compared to imipenem, making it suitable for treating bacterial meningitis 6
- For multidrug-resistant gram-negative infections, newer agents like ceftazidime-avibactam or meropenem-vaborbactam may be preferred 6, 3
Meropenem's broad spectrum of activity makes it an important option for empiric therapy of serious infections, but its use should be judicious to prevent development of resistance.