Treatment of E. coli Bacteremia

For patients with E. coli bacteremia, piperacillin-tazobactam is the recommended first-line intravenous antibiotic treatment. 1

Initial Empiric Therapy

Piperacillin-tazobactam 4.5g IV every 6 hours is the preferred empiric treatment for E. coli bacteremia 1, 2
Alternative options for non-critically ill patients with community-acquired infection include:
- Ceftriaxone 2g IV daily plus metronidazole 500mg IV every 6 hours 1, 3
- Cefotaxime 2g IV every 8 hours plus metronidazole 500mg IV every 6 hours 1, 3
- Ciprofloxacin 400mg IV every 8 hours plus metronidazole 500mg IV every 6 hours (for patients with beta-lactam allergies) 1, 4

For critically ill patients or those with sepsis, use broad-spectrum antibiotics that cover gram-negative bacilli 3
For patients with healthcare-associated infections or recent colonization with multidrug-resistant pathogens, consider using two antimicrobial agents of different classes with gram-negative activity as initial therapy 3
For patients with E. coli bacteremia involving a long-term catheter and persistent bacteremia or severe sepsis, remove the device and extend antibiotic therapy beyond the standard duration 3

For patients with E. coli endocarditis, combination therapy with either ampicillin or a broad-spectrum cephalosporin with an aminoglycoside (usually gentamicin) is recommended 3, 1
Third-generation cephalosporins, such as ceftriaxone, have shown effectiveness in experimental models of E. coli endocarditis 1

For healthcare-associated infections, empiric coverage should be guided by local microbiologic results 3
Options include carbapenems (imipenem-cilastatin, meropenem, doripenem), piperacillin-tazobactam, or ceftazidime/cefepime plus metronidazole 3

Monitor clinical response within 48-72 hours of initiating therapy 1
Adjust therapy based on culture and susceptibility results when available 1
De-escalate the initial regimen to a single appropriate antibiotic once culture and susceptibility results are available 3

Recent research suggests that empiric cefuroxime treatment of E. coli bacteremia was associated with higher 14-day mortality compared to piperacillin-tazobactam 5
Ampicillin-sulbactam is not recommended due to high rates of resistance among community-acquired E. coli 3
Quinolone-resistant E. coli is increasingly common, and quinolones should not be used unless local susceptibility rates exceed 90% 1, 3
Consider local resistance patterns when selecting empiric therapy, as inappropriate initial therapy can lead to treatment failure 6
Source control is an essential component of treatment for E. coli bacteremia 1

Due to increasing resistance of E. coli to fluoroquinolones, review local population susceptibility profiles and isolate susceptibility when available 3
Extended-spectrum β-lactamase (ESBL)-producing E. coli may require carbapenem therapy, although recent studies suggest piperacillin-tazobactam may be effective in some cases 7
For patients with prior amoxicillin or amoxicillin/clavulanate exposure, be aware of increased risk of piperacillin-tazobactam resistance 6