What is the recommended treatment for an uncomplicated urinary tract infection (UTI) caused by Escherichia coli (E. coli) with the given antibiotic susceptibility profile?

From the Guidelines

For an uncomplicated urinary tract infection caused by E. coli, the recommended first-line treatment is nitrofurantoin 100 mg orally twice daily for 5 days, as it is effective and less likely to produce collateral damage 1. The given antibiotic susceptibility profile shows that the E. coli is susceptible to nitrofurantoin, with an MIC of <=16, making it a suitable choice for treatment.

• Other effective options include:
  • Trimethoprim-sulfamethoxazole (TMP-SMX) 160/800 mg (one double-strength tablet) orally twice daily for 3 days, as the E. coli is susceptible to TMP-SMX with an MIC of <=20 1.
  • Fosfomycin 3 grams as a single oral dose, which has been shown to be effective in treating UTIs and has a low propensity for collateral damage 1.
• Fluoroquinolones like ciprofloxacin should be reserved for more complicated infections due to concerns about resistance and side effects, as the E. coli is resistant to ciprofloxacin with an MIC of >=4 1. When taking nitrofurantoin, patients should take it with food to minimize gastrointestinal side effects and complete the full course even if symptoms improve.
• Increased fluid intake helps flush bacteria from the urinary tract. These antibiotics work by either inhibiting bacterial cell wall synthesis, protein synthesis, or folate metabolism, effectively eliminating the E. coli causing the infection.
• Treatment should begin promptly to prevent the infection from ascending to the kidneys, and the duration of treatment should be as short as reasonable, generally no longer than seven days 1.

From the FDA Drug Label

1. 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.

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 It is recommended that initial episodes of uncomplicated urinary tract infections be treated with a single effective antibacterial agent rather than the combination

The recommended treatment for an uncomplicated urinary tract infection (UTI) caused by Escherichia coli (E. coli) with the given antibiotic susceptibility profile is:

• Levofloxacin is not recommended due to resistance (R) with an MIC of >=8
• Trimethoprim/Sulfamethoxazole may be considered as the E. coli isolate is susceptible (S) to this antibiotic combination with an MIC of <=20 2
• Other susceptible antibiotics such as Amox/Clavulanate, Amp/Sulbactam, Cefazolin, Cefepime, Ceftazidime, Ceftriaxone, Gentamicin, Imipenem, Meropenem, Nitrofurantoin, or Pip/Tazobactam may also be considered for treatment 3

From the Research

Antibiotic Susceptibility Profile

The given antibiotic susceptibility profile for the Escherichia coli (E. coli) isolate is as follows:

• Amoxicillin-clavulanic acid (AMOX/CLAVULANATE): Sensitive (S) with a minimum inhibitory concentration (MIC) of <=2
• Ampicillin-sulbactam (AMP/SULBACTAM): Sensitive (S) with a MIC of <=2
• Cefazolin (CEFAZOLIN): Not reported as sensitive or resistant, with a MIC of <=4 **2
• Cefepime (CEFEPIME): Sensitive (S) with a MIC of <=0.12
• Ceftazidime (CEFTAZIDIME): Sensitive (S) with a MIC of <=1
• Ceftriaxone (CEFTRIAXONE): Sensitive (S) with a MIC of <=0.25
• Ciprofloxacin (CIPROFLOXACIN): Resistant (R) with a MIC of >=4
• Gentamicin (GENTAMICIN): Sensitive (S) with a MIC of <=1
• Imipenem (IMIPENEM): Sensitive (S) with a MIC of <=0.25
• Levofloxacin (LEVOFLOXACIN): Resistant (R) with a MIC of >=8
• Meropenem (MEROPENEM): Sensitive (S) with a MIC of <=0.25
• Nitrofurantoin (NITROFURANTOIN): Sensitive (S) with a MIC of <=16
• Piperacillin-tazobactam (PIP/TAZOBACTAM): Sensitive (S) with a MIC of <=4
• Trimethoprim-sulfamethoxazole (TRIMETHOPRIM/SULFA): Sensitive (S) with a MIC of <=20

Recommended Treatment

Based on the antibiotic susceptibility profile, the recommended treatment for an uncomplicated urinary tract infection (UTI) caused by E. coli is:

• Nitrofurantoin (NITROFURANTOIN) 4
• Fosfomycin (not listed in the given antibiotic susceptibility profile, but recommended in 4)
• Cefepime (CEFEPIME) 5
• Meropenem (MEROPENEM) 6
• Amikacin (not listed in the given antibiotic susceptibility profile, but recommended in 7)

Considerations

When selecting an antibiotic for treatment, it is essential to consider the local resistance patterns and the patient's medical history, including any previous UTIs, hospitalizations, or antibiotic use 8, 7. Additionally, the risk factors for extended-spectrum β-lactamase (ESBL)-producing E. coli, such as hospital-acquired infection, prior UTI within 1 year, and underlying cerebrovascular disease, should be taken into account 7.

Key Points

• The E. coli isolate is resistant to ciprofloxacin and levofloxacin, which are commonly used to treat UTIs.
• The isolate is sensitive to several antibiotics, including amoxicillin-clavulanic acid, ampicillin-sulbactam, cefepime, ceftazidime, ceftriaxone, gentamicin, imipenem, meropenem, nitrofurantoin, and piperacillin-tazobactam.
• The treatment should be guided by the antibiotic susceptibility profile and local resistance patterns 4, 8, 5, 6, 7.