What is the recommended treatment for a patient with a fluoroquinolone-resistant Escherichia coli (E. coli) urinary tract infection (UTI) with 50,000-100,000 colony-forming units per milliliter (CFU/mL)?

From the Guidelines

For a patient with a fluoroquinolone-resistant E. coli UTI with 50,000-100,000 CFU/mL, the recommended treatment is nitrofurantoin for 5 days, as it is susceptible with an MIC of <=16, according to the provided antimicrobial susceptibility testing results. The patient's urine culture shows susceptibility to nitrofurantoin, making it a suitable choice for treatment 1. Given the fluoroquinolone resistance, alternative antibiotics such as nitrofurantoin are preferred, as recommended by the American College of Physicians 1. Some key points to consider in the treatment of this patient include:

• The IDSA/ESCMID guideline recommends treatment durations depending on the type of antibiotic, including 5 days of nitrofurantoin for uncomplicated cystitis 1.
• Nitrofurantoin is effective against E. coli, which accounts for more than 75% of all bacterial cystitis 1.
• Ensure adequate hydration during treatment and advise the patient to complete the full course of antibiotics even if symptoms resolve earlier.
• Follow-up urine culture may be warranted in complicated cases or if symptoms persist after completing treatment. Other treatment options, such as trimethoprim-sulfamethoxazole (TMP-SMX), may not be suitable due to the high MIC of >=320, indicating resistance 1. Parenteral therapy with a carbapenem or a third-generation cephalosporin may be necessary if the patient has signs of pyelonephritis or systemic infection, but this is not indicated in the provided information.

From the FDA Drug Label

Culture and susceptibility testing performed periodically during therapy will provide information about the continued susceptibility of the pathogens to the antimicrobial agent and also the possible emergence of bacterial resistance.

1. 9 Complicated Urinary Tract Infections: 5 Day Treatment Regimen Levofloxacin tablets are indicated for the treatment of complicated urinary tract infections due to Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis
2. 12 Uncomplicated Urinary Tract Infections Levofloxacin tablets are indicated for the treatment of uncomplicated urinary tract infections (mild to moderate) due to Escherichia coli, Klebsiella pneumoniae, or Staphylococcus saprophyticus.

The patient has a fluoroquinolone-resistant Escherichia coli urinary tract infection (UTI). Given the resistance pattern, levofloxacin is not a suitable option.

• The MIC values provided for other antibiotics are as follows:
  • AMOX/CLAVULANATE: 8
  • AMP/SULBACTAM: 8
  • CEFAZOLIN: <=4
  • CEFEPIME: <=0.12
  • CEFTAZIDIME: <=1
  • CEFTRIAXONE: <=0.25
  • CIPROFLOXACIN: >=4
  • GENTAMICIN: <=1
  • IMIPENEM: <=0.25
  • LEVOFLOXACIN: >=8
  • MEROPENEM: <=0.25
  • NITROFURANTOIN: <=16
  • PIP/TAZOBACTAM: <=4
  • TRIMETHOPRIM/SULFA: >=320 Considering the provided MIC values, potential treatment options could be CEFEPIME, CEFTAZIDIME, CEFTRIAXONE, GENTAMICIN, IMIPENEM, MEROPENEM, or PIP/TAZOBACTAM. However, the choice of antibiotic should be based on the patient's specific clinical situation, local resistance patterns, and other factors. 2

From the Research

Treatment Options for Fluoroquinolone-Resistant E. coli UTI

• The patient has a fluoroquinolone-resistant Escherichia coli (E. coli) urinary tract infection (UTI) with 50,000-100,000 colony-forming units per milliliter (CFU/mL) 3, 4.
• According to the provided antimicrobial susceptibility results, the E. coli isolate is resistant to ciprofloxacin and levofloxacin, but susceptible to nitrofurantoin, amoxicillin-clavulanate, and other antibiotics.

Recommended Treatment

• Nitrofurantoin is a recommended treatment option for uncomplicated UTIs, including those caused by fluoroquinolone-resistant E. coli 3, 4.
• Other treatment options for fluoroquinolone-resistant E. coli UTI include amoxicillin-clavulanate, cephalosporins, and carbapenems 4, 5.
• The choice of empiric antibiotic therapy should be based on local antibiogram data and patient-specific factors, such as prior antibiotic use and underlying medical conditions 5, 6.

Considerations

• The high prevalence of resistance to first-line antibiotics, such as ampicillin, cotrimoxazole, and ciprofloxacin, highlights the need for alternative treatment options 7.
• Nitrofurantoin has been shown to be effective against E. coli UTIs, with a low resistance rate of 2.3% 3.
• Prior exposure to fluoroquinolones and recurrent UTIs are risk factors for fluoroquinolone-resistant E. coli UTI, and alternative treatment options should be considered in these cases 6.