What is the initial antibiotic treatment approach for suspected or confirmed E.coli (Escherichia coli) or Klebsiella infections?

From the Guidelines

The initial antibiotic treatment for suspected or confirmed E. coli or Klebsiella infections should involve empiric therapy with broad-spectrum antibiotics, such as intravenous beta-lactams like ceftriaxone or piperacillin-tazobactam, or a carbapenem like meropenem, until culture and sensitivity results are available 1.

Key Considerations

• The choice of antibiotics should consider local resistance patterns, infection site, and patient factors like allergies and renal function.
• In areas with high ESBL prevalence, carbapenems may be necessary as initial therapy.
• Treatment duration typically ranges from 7-14 days depending on infection severity and site, with longer courses for complicated infections.
• The treatment should be de-escalated to narrower-spectrum agents once susceptibility results are available to reduce resistance development.

Antibiotic Options

• For uncomplicated urinary tract infections, oral fluoroquinolones or trimethoprim-sulfamethoxazole may be used as first-line options.
• For more severe infections like bacteremia, sepsis, or complicated intra-abdominal infections, intravenous beta-lactams or carbapenems are recommended.
• Other options include aminoglycosides, tigecycline, and newer antibiotics like ceftolozone/tazobactam and ceftazidime/avibactam.

Resistance Considerations

• Increasing antimicrobial resistance, particularly extended-spectrum beta-lactamase (ESBL) producing strains, is a major concern.
• Local resistance patterns and susceptibility testing should guide the choice of antibiotics.
• The use of carbapenems should be limited to preserve their activity against multidrug-resistant infections.

From the FDA Drug Label

Tobramycin for Injection is indicated for the treatment of septicemia caused by susceptible isolates of P. aeruginosa, E. coli, and Klebsiella spp., in adult and pediatric patients. Tobramycin for Injection is indicated for the treatment of lower respiratory tract infections caused by susceptible isolates of P. aeruginosa, Klebsiella spp., Enterobacter spp., Serratia spp., E. coli, and S. aureus in adult and pediatric patients. Gentamicin Injection, USP is indicated in the treatment of serious infections caused by susceptible strains of the following microorganisms: Pseudomonas aeruginosa, Proteus species (indole-positive and indole-negative), Escherichia coli, Klebsiella-Enterobacter-Serratia species, Citrobacter species and Staphylococcus species (coagulase-positive and coagulase-negative)

The initial antibiotic treatment approach for suspected or confirmed E.coli or Klebsiella infections may include Tobramycin or Gentamicin, as these drugs are indicated for the treatment of serious infections caused by these microorganisms 2 3.

• Key considerations:
  • Susceptibility testing should be performed to confirm the effectiveness of the chosen antibiotic.
  • The decision to continue therapy with these drugs should be based on the results of susceptibility tests, the severity of the infection, and important additional concepts contained in the warnings and precautions.
  • In serious infections when the causative organisms are unknown, these drugs may be administered as initial therapy in conjunction with other antibiotics before obtaining results of susceptibility testing.

From the Research

Initial Antibiotic Treatment Approach

The initial antibiotic treatment approach for suspected or confirmed E.coli (Escherichia coli) or Klebsiella infections depends on various factors, including the severity of the infection, patient's medical history, and local antimicrobial resistance patterns.

• For acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females, the recommended first-line empiric antibiotic therapy includes:
  • A 5-day course of nitrofurantoin
  • A 3-g single dose of fosfomycin tromethamine
  • A 5-day course of pivmecillinam 4
• For extended-spectrum β-lactamases (ESBLs)-producing E coli, treatment oral options include:
  • Nitrofurantoin
  • Fosfomycin
  • Pivmecillinam
  • Amoxicillin-clavulanate
  • Finafloxacin
  • Sitafloxacin 4
• For ESBLs-producing Klebsiella pneumoniae, treatment oral options include:
  • Pivmecillinam
  • Fosfomycin
  • Finafloxacin
  • Sitafloxacin 4
• Parenteral treatment options for UTIs due to ESBLs-producing Enterobacteriales include:
  • Piperacillin-tazobactam (for ESBL-E coli only)
  • Carbapenems (including meropenem/vaborbactam, imipenem/cilastatin-relebactam, and sulopenem)
  • Ceftazidime-avibactam
  • Ceftolozane-tazobactam
  • Aminoglycosides (including plazomicin)
  • Cefiderocol
  • Fosfomycin
  • Sitafloxacin
  • Finafloxacin 4

Resistance Patterns

Resistance patterns of E. coli and Klebsiella pneumoniae vary by region and over time.

• A study found that the frequency of ESBL-producing E. coli strains was 24% 5
• Another study found that the susceptibility of E. coli to amoxicillin/clavulanic acid decreased from 62.9% to 40.0% over an 8-year period 6
• The same study found that the susceptibility of E. coli to ciprofloxacin decreased from 100% to 40.0% over the same period 6

Treatment Options for Carbapenem-Resistant Infections

For carbapenem-resistant E. coli and K. pneumoniae infections, treatment options include:

• Combination therapy with a carbapenem and an active colistin, tigecycline, or fosfomycin 7
• Tigecycline, colistin, and fosfomycin have shown high activity against carbapenem-resistant E. coli and K. pneumoniae isolates 7