Ertapenem Lack of Coverage Against Pseudomonas aeruginosa

Classification and Spectrum of Activity

Ertapenem is a Group 1 carbapenem antibiotic with a broad spectrum of activity against many Gram-positive and Gram-negative bacteria, but it specifically lacks activity against Pseudomonas aeruginosa 1, 2
Carbapenems are classified into different groups based on their antimicrobial spectrum, with Group 1 carbapenems (ertapenem) being active against extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae but not against Pseudomonas aeruginosa and Enterococcus species 1, 2
Group 2 carbapenems (imipenem/cilastatin, meropenem, doripenem) have activity against non-fermentative Gram-negative bacilli including Pseudomonas aeruginosa 1, 2

The World Society of Emergency Surgery (WSES) guidelines state that ertapenem "has activity against extended-spectrum beta-lactamase (ESBL)-producing pathogens, but not active against P. aeruginosa and Enterococcus species" 1, 2

For infections where Pseudomonas aeruginosa is a concern, the World Society of Emergency Surgery recommends using Group 2 carbapenems (imipenem, meropenem, doripenem) instead of ertapenem 1, 2
Alternative anti-pseudomonal options include antipseudomonal cephalosporins (ceftazidime, cefepime), piperacillin-tazobactam, aminoglycosides, or ciprofloxacin/levofloxacin 1, 3
For hospital-acquired or ventilator-associated pneumonia where P. aeruginosa is a concern, guidelines recommend antipseudomonal cephalosporins, acylureidopenicillin/β-lactamase inhibitors, or Group 2 carbapenems plus either ciprofloxacin or a macrolide with an aminoglycoside 3, 4
Ertapenem remains an appropriate choice for community-acquired infections where ESBL-producing Enterobacteriaceae are a concern but Pseudomonas aeruginosa is unlikely 5, 6

The European Respiratory Society recommends using ertapenem as monotherapy for low-risk hospital-acquired pneumonia (HAP/VAP) in patients without septic shock and low risk for multidrug-resistant pathogens 7
The Infectious Diseases Society of America recommends ertapenem 1g IV daily for mild-to-moderate severity community-acquired intra-abdominal infections 8

For hospital-acquired or ventilator-associated pneumonia where Pseudomonas aeruginosa is a concern, the European Respiratory Society recommends using imipenem, meropenem, cefepime, piperacillin/tazobactam, or ceftazidime instead of ertapenem 7
For severe infections requiring dual Gram-negative coverage, the European Respiratory Society recommends combining an antipseudomonal β-lactam with either ciprofloxacin or an aminoglycoside 7
For ICU patients with septic shock, dual antipseudomonal therapy is mandatory, and ertapenem has no role, according to the European Respiratory Society 7