Effectiveness of Ceftriaxone Against Enterobacteriaceae
Ceftriaxone is effective against most Enterobacteriaceae species and is indicated for intra-abdominal infections caused by susceptible Enterobacteriaceae, including Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis, though resistance concerns exist with certain species like Enterobacter. 1, 2
Spectrum of Activity Against Enterobacteriaceae
Susceptible Enterobacteriaceae
- FDA-approved for infections caused by:
Effectiveness Data
- Clinical studies have demonstrated high efficacy rates:
Important Limitations and Resistance Concerns
Enterobacter Species Concerns
- Ceftriaxone has limited activity against Enterobacter cloacae 5
- Resistance can develop during therapy with Enterobacter species 3
- First and second-generation cephalosporins are generally not effective against Enterobacter infections 7
- Even third-generation cephalosporins like ceftriaxone are not recommended for Enterobacter due to increased likelihood of resistance, particularly for E. cloacae and E. aerogenes 7
ESBL-Producing Enterobacteriaceae
- In settings with high incidence of ESBL-producing Enterobacteriaceae, extended use of cephalosporins including ceftriaxone should be discouraged 7
- Ceftriaxone use should be limited to pathogen-directed therapy due to selection pressure resulting in emergence of resistance 7
- New cephalosporin/beta-lactamase inhibitor combinations (ceftolozane/tazobactam and ceftazidime/avibactam) have stronger activity against ESBL-producing Enterobacteriaceae 7
Clinical Application in Intra-abdominal Infections
Recommended Use
- Third-generation cephalosporins including ceftriaxone in association with metronidazole are options for treating mild intra-abdominal infections 7
- For community-acquired intra-abdominal infections, ceftriaxone with metronidazole is an appropriate empiric choice 7
Alternative Regimens
- For mild to moderate infections: amoxicillin-clavulanic acid (first choice) or ciprofloxacin with metronidazole (second choice) 7
- For severe infections: cefotaxime or ceftriaxone with metronidazole (first choice) or piperacillin-tazobactam (first choice) 7
- For multidrug-resistant infections: carbapenems (meropenem, imipenem) are preferred 7
Practical Considerations
Dosing Advantages
- Long half-life allows for once or twice daily administration 6, 8
- No dosage adjustment needed for renal insufficiency when using doses of 2g or less per day 9
Monitoring and Resistance Prevention
- To reduce development of drug-resistant bacteria, ceftriaxone should be used only for proven or strongly suspected infections caused by susceptible bacteria 1
- When culture and susceptibility information become available, antimicrobial therapy should be adjusted accordingly 1
- Patients should be reassessed when microbiological results are available, with consideration for de-escalation or withdrawal of antimicrobial therapy 7
Summary
Ceftriaxone remains effective against most common Enterobacteriaceae in clinical practice but should be used judiciously due to emerging resistance concerns, particularly with ESBL-producing strains and Enterobacter species. For empiric therapy of infections potentially caused by Enterobacteriaceae, local resistance patterns should guide treatment decisions, with appropriate de-escalation once culture results are available.