What is the appropriate antibiotic coverage for Escherichia coli (E. coli) urinary tract infections (UTIs)?

From the Guidelines

For E. coli urinary tract infection coverage, clinicians should prescribe short-course antibiotics with either nitrofurantoin for 5 days, trimethoprim–sulfamethoxazole (TMP–SMZ) for 3 days, or fosfomycin as a single dose for uncomplicated cystitis, as recommended by the American College of Physicians 1. When considering antibiotic coverage for E. coli UTIs, it's essential to differentiate between uncomplicated and complicated infections.

• Uncomplicated cystitis can be treated with nitrofurantoin, TMP-SMZ, or fosfomycin, as these antibiotics target E. coli, which accounts for more than 75% of all bacterial cystitis 1.
• For uncomplicated pyelonephritis, fluoroquinolones or TMP-SMZ can be used, with treatment durations of 5 to 7 days or 14 days, respectively, based on antibiotic susceptibility 1. Key factors to consider when selecting an antibiotic include:
• Local resistance patterns
• Patient allergies
• Infection severity
• The potential for adverse effects, such as those associated with fluoroquinolones 1. It's crucial to note that E. coli can develop resistance, making culture and sensitivity testing important for recurrent or complicated infections 1. Patients should complete the full antibiotic course and increase fluid intake to help flush bacteria from the urinary tract. In cases where patients have a history of resistant organisms, alternative antibiotics like fluoroquinolones may be reserved for use 1.

From the FDA Drug Label

To reduce the development of drug-resistant bacteria and maintain the effectiveness of sulfamethoxazole and trimethoprim tablets and other antibacterial drugs, sulfamethoxazole and trimethoprim tablets should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to empiric selection of therapy Urinary Tract Infections For the treatment of urinary tract infections due to susceptible strains of the following organisms: Escherichia coli, Klebsiella species, Enterobacter species, Morganella morganii, Proteus mirabilis and Proteus vulgaris Amoxicillin and clavulanate potassium tablets USP is a combination penicillin-class antibacterial and beta-lactamase inhibitor indicated in the treatment of infections due to susceptible isolates of the designated bacteria in the conditions listed below*: 1.5 Urinary Tract Infections – caused by beta-lactamase–producing isolates of E. coli, Klebsiella species, and Enterobacter species.

The appropriate antibiotic coverage for Escherichia coli (E. coli) urinary tract infections (UTIs) includes:

• Trimethoprim-sulfamethoxazole 2
• Amoxicillin-clavulanate 3 for beta-lactamase–producing isolates of E. coli Key considerations:
• The choice of antibiotic should be based on culture and susceptibility information when available
• Local epidemiology and susceptibility patterns should be considered in the absence of such data

From the Research

Antibiotic Coverage for E. coli UTIs

The appropriate antibiotic coverage for Escherichia coli (E. coli) urinary tract infections (UTIs) depends on various factors, including the severity of the infection, patient characteristics, and local antimicrobial resistance patterns.

• First-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females includes:
  • Nitrofurantoin 4, 5, 6, 7
  • Fosfomycin tromethamine 4, 5
  • Pivmecillinam 4
• Second-line options include:
  • Oral cephalosporins such as cephalexin or cefixime 4
  • Fluoroquinolones 4, 8
  • β-lactams, such as amoxicillin-clavulanate 4, 8
• For UTIs due to extended-spectrum β-lactamase (ESBL)-producing E. coli, treatment options include:
  • Nitrofurantoin 4, 5, 6, 7
  • Fosfomycin 4, 5
  • Pivmecillinam 4
  • Amoxicillin-clavulanate 4
  • Finafloxacin 4
  • Sitafloxacin 4
• Parenteral treatment options for UTIs due to ESBL-producing Enterobacteriales include:
  • Piperacillin-tazobactam (for ESBL-E coli only) 4
  • Carbapenems, including meropenem/vaborbactam, imipenem/cilastatin-relebactam, and sulopenem 4
  • Ceftazidime-avibactam 4
  • Ceftolozane-tazobactam 4
  • Aminoglycosides, including plazomicin 4
  • Cefiderocol 4
  • Fosfomycin 4
  • Sitafloxacin 4
  • Finafloxacin 4

Resistance Patterns

• High rates of resistance to trimethoprim-sulfamethoxazole and ciprofloxacin have been reported, making them less suitable for empiric treatment of UTIs 4, 6, 7
• Nitrofurantoin has been shown to retain antimicrobial activity against multidrug-resistant urinary E. coli, with resistance rates ranging from 2.1% to 24.1% 7
• Fosfomycin has also been reported to have low resistance rates, with 0% resistance observed in some studies 5