Cefdinir for E. coli Infections
Cefdinir is effective against Escherichia coli (E. coli) infections and can be used as a treatment option for uncomplicated urinary tract infections caused by this pathogen.
Antimicrobial Activity Against E. coli
- Cefdinir exhibits in vitro minimum inhibitory concentrations (MICs) of 1 mcg/mL or less against ≥90% of E. coli strains, though the FDA notes that clinical effectiveness for treating E. coli infections has not been fully established in controlled clinical trials 1
- Cefdinir demonstrated 98.7% susceptibility against E. coli isolates from community-acquired urinary tract infections in North America, making it one of the most active oral agents tested 2
- Cefdinir is 8-16 times more potent than cefuroxime axetil and cefprozil against E. coli, showing superior activity compared to many other oral cephalosporins 2
Clinical Applications for E. coli Infections
- For urinary tract infections caused by E. coli, cefdinir has shown promising clinical efficacy with high urinary concentrations that exceed the MIC needed to eradicate E. coli 3
- In pediatric patients with complicated urinary tract infections (many caused by E. coli), prophylactic cefdinir at 3 mg/kg once daily was effective with a 93% recurrence-free rate over 6 months 3
- Even the lowest measured urinary cefdinir concentration (1.16 µg/mL) in clinical studies was sufficient to eradicate E. coli strains 3
Mechanism of Action and Resistance
- As with other cephalosporins, cefdinir's bactericidal activity results from inhibition of bacterial cell wall synthesis 1
- Cefdinir is stable to hydrolysis by many β-lactamase enzymes, making it effective against some organisms resistant to penicillins and certain cephalosporins 1
- Cefdinir showed superior activity against E. coli strains harboring extended-spectrum plasmid-mediated beta-lactamases compared to ampicillin, cephalexin, and cefuroxime 4
Treatment Considerations for E. coli Infections
- For severe E. coli infections like infective endocarditis, third-generation cephalosporins (which include cefdinir) are recommended as effective options 5
- For Gram-negative infections including E. coli, guidelines recommend an extended-spectrum cephalosporin (like cefdinir) together with an aminoglycoside for serious infections 5
- Dosage adjustment is necessary for patients with markedly compromised renal function (creatinine clearance <30 mL/min) as cefdinir is predominantly eliminated via renal excretion 1
Limitations and Caveats
- While cefdinir is active against E. coli, it is inactive against most strains of Enterobacter species, Pseudomonas species, and Enterococcus species 1
- For severe E. coli infections like endocarditis, cardiac surgery in combination with prolonged courses of combined antibiotic therapy may be necessary 5
- The specific choice of antibiotic should be guided by susceptibility testing of the isolate, especially for serious infections 5
Practical Recommendations
- For uncomplicated E. coli urinary tract infections, cefdinir can be an effective treatment option with high urinary concentrations that exceed the MIC needed for eradication 2, 3
- For more serious E. coli infections, combination therapy with an aminoglycoside may be warranted, particularly for bacteremia or endocarditis 5
- Monitoring renal function is important as cefdinir requires dose adjustment in patients with renal impairment 1