From the Guidelines
Trimethoprim-sulfamethoxazole (TMP-SMX) is the recommended antibiotic for treating urinary tract infections caused by lactose-positive coliforms, such as Escherichia coli, due to its efficacy and safety profile, as supported by the American College of Physicians' best practice advice 1. The typical dosage for uncomplicated cases is one double-strength tablet (160 mg trimethoprim/800 mg sulfamethoxazole) twice daily for 3 days.
- Alternatives to TMP-SMX include:
- Nitrofurantoin (100 mg twice daily for 5 days)
- Fosfomycin (3 gram single dose)
- Fluoroquinolones like ciprofloxacin (250-500 mg twice daily for 5-7 days) when resistance patterns warrant their use, as suggested by the IDSA/ESCMID guideline 1. Before starting treatment, it's essential to ensure adequate hydration and consider obtaining a urine culture in complicated cases or recurrent infections.
- Key considerations for antibiotic selection include:
- Local resistance patterns
- Patient's medical history and potential allergies
- Severity of the infection As noted in the study published in the Annals of Internal Medicine 1, TMP-SMX is a highly effective option for treating uncomplicated urinary tract infections, but local resistance patterns should guide antibiotic selection to ensure the best possible outcome.
From the FDA Drug Label
Levofloxacin tablets are indicated in adult patients for the treatment of uncomplicated urinary tract infections (mild to moderate) due to Escherichia coli, Klebsiella pneumoniae, or Staphylococcus saprophyticus. Levofloxacin tablets are indicated in adult patients for the treatment of complicated urinary tract infections due to Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis Levofloxacin tablets are indicated in adult patients for the treatment of acute pyelonephritis caused by Escherichia coli, including cases with concurrent bacteremia
Levofloxacin is effective against urinary tract infections caused by lactose-positive coliforms, such as Escherichia coli (E. coli) 2.
- Key points:
- Effective against uncomplicated and complicated urinary tract infections
- Effective against acute pyelonephritis caused by E. coli
- Should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria
From the Research
Antibiotic Options for Urinary Tract Infections with Lactose-Positive Coliforms
- The recommended first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females includes a 5-day course of nitrofurantoin, a 3-g single dose of fosfomycin tromethamine, or a 5-day course of pivmecillinam 3.
- High rates of resistance to trimethoprim-sulfamethoxazole and ciprofloxacin preclude their use as empiric treatment of UTIs in several communities, particularly if patients were recently exposed to them or are at risk of infections with extended-spectrum β-lactamases (ESBLs)-producing Enterobacteriales 3.
- Second-line options include oral cephalosporins such as cephalexin or cefixime, fluoroquinolones, and β-lactams, such as amoxicillin-clavulanate 3.
- For patients with UTI requiring hospitalization, ceftriaxone seems to be an effective empiric therapy for most patients 4.
- A 3-day regimen of amoxicillin-clavulanate is not as effective as ciprofloxacin for the treatment of acute uncomplicated cystitis, even in women infected with susceptible strains 5.
- Risk factors for ciprofloxacin resistance among Escherichia coli strains isolated from community-acquired urinary tract infections include use of quinolones more than once within the last year, living in a rural area, having a urinary catheter, age >50, and complicated infections 6.
- Empirical use of fluoroquinolones in uUTI should be discouraged because of increased antimicrobial resistance rates 7.
Considerations for Antibiotic Selection
- Local antibiogram data should guide the choice of empiric antibiotic therapy 4.
- Fluoroquinolone-sparing agents such as nitrofurantoin and fosfomycin should be evaluated as alternative therapies 6.
- Treatment durations should be in line with recommended courses to minimize the development of resistance 7.