Treatment of Urinary Tract Infections
For acute uncomplicated UTIs in women, use nitrofurantoin, trimethoprim-sulfamethoxazole (TMP-SMX), or fosfomycin as first-line therapy for no longer than 7 days, with treatment selection based on local antibiogram patterns. 1
First-Line Antibiotic Selection
The three recommended first-line agents are equally effective at achieving clinical and bacteriological cure, but differ significantly in their resistance profiles and collateral damage potential 1:
- Nitrofurantoin: 5-day course, demonstrates remarkably low resistance rates (only 2.6% prevalence with initial infection, 20.2% at 3 months, and 5.7% at 9 months) 1
- TMP-SMX: 3-day course, though high resistance rates (78.3% persistent resistance) in some communities may preclude its use 1
- Fosfomycin: Single 3-gram dose 1, 2
Critical consideration: Fluoroquinolones should NOT be used for uncomplicated UTIs due to FDA advisory warnings about disabling and serious adverse effects that create an unfavorable risk-benefit ratio, including altered fecal microbiota and Clostridium difficile infection 1. Beta-lactam antibiotics are also not first-line due to collateral damage effects and propensity to promote more rapid UTI recurrence 1.
Treatment Duration and Approach
- Keep treatment courses short: Generally no longer than 7 days for acute cystitis episodes 1
- Obtain urine culture and sensitivity before initiating treatment to guide therapy based on bacterial antimicrobial sensitivities 1
- Patient-initiated treatment (self-start) may be offered to select reliable patients while awaiting culture results 1
Second-Line Options
When first-line agents are contraindicated due to resistance patterns or allergies 1:
- Oral cephalosporins (cephalexin, cefixime)
- Fluoroquinolones (only when absolutely necessary)
- Amoxicillin-clavulanate
Resistant Organisms
For culture-proven resistance to oral antibiotics, use culture-directed parenteral antibiotics for as short a course as reasonable, generally no longer than 7 days 1.
For ESBL-producing organisms, oral options include nitrofurantoin, fosfomycin, pivmecillinam, and amoxicillin-clavulanate (for E. coli only) 2.
Critical Pitfalls to Avoid
Do NOT treat asymptomatic bacteriuria in non-pregnant women, even those with recurrent UTIs, as this increases symptomatic infection risk, bacterial resistance, and healthcare costs 1. The only exceptions are pregnant women and patients scheduled for invasive urinary procedures 1.
Do NOT perform surveillance urine testing in asymptomatic patients with recurrent UTIs 1.
Avoid classifying recurrent UTI patients as "complicated" unless they have structural/functional urinary tract abnormalities, immunosuppression, or pregnancy, as this leads to unnecessary broad-spectrum antibiotic use 1.
Recurrent UTI Prevention
Following acute treatment, antibiotic prophylaxis may be prescribed after discussing risks, benefits, and alternatives 1:
- Daily prophylaxis: TMP, TMP-SMX, nitrofurantoin, or cephalexin for 6-12 months 1
- Post-coital prophylaxis: Low-dose antibiotic within 2 hours of sexual activity for premenopausal women with coitus-related infections 1
- Fosfomycin prophylaxis: Dosed every 10 days 1
Important adverse event consideration: Nitrofurantoin carries extremely low but serious risks of pulmonary (0.001%) and hepatic (0.0003%) toxicity 1.
Special Populations
Postmenopausal women: Consider vaginal estrogen with or without lactobacillus-containing probiotics as first-line prevention strategy 1.
Pediatric patients (2-24 months with febrile UTI): Use oral amoxicillin-clavulanate, TMP-SMX, or cephalosporins for 7-14 days; avoid nitrofurantoin as it doesn't achieve adequate parenchymal concentrations for pyelonephritis 1.