What is the recommended treatment for an adult female with a urinary tract infection (UTI)?

Treatment of Urinary Tract Infection in Adult Females

For an adult female with an acute uncomplicated UTI, initiate empiric therapy with nitrofurantoin for 5 days, trimethoprim-sulfamethoxazole for 3 days (only if local resistance is <20%), or fosfomycin as a single 3-gram dose, while obtaining a urine culture before starting antibiotics. 1

Initial Diagnostic Approach

• Obtain urine culture and sensitivity before initiating treatment to establish baseline pathogen identification and guide therapy if symptoms persist 2, 1
• Look specifically for acute-onset dysuria (>90% accuracy for UTI when present without vaginal symptoms), along with variable degrees of urgency, frequency, hematuria, or new incontinence 2
• Do not obtain cystoscopy or upper tract imaging routinely in uncomplicated UTI 2

First-Line Antibiotic Selection

The choice depends on local antibiogram patterns and prior culture data:

• Nitrofurantoin: Preferred first-line agent due to low resistance rates and minimal collateral damage to normal flora; use for 5 days 1, 3, 4
• Trimethoprim-sulfamethoxazole (TMP-SMX): 1 double-strength tablet every 12 hours for 3 days, but only if local resistance is documented <20% 1, 5, 6
• Fosfomycin tromethamine: Single 3-gram dose, particularly useful when resistance to other agents is high 1, 3, 4

Avoid fluoroquinolones and cephalosporins as first-line agents due to increasing resistance, collateral damage to normal flora, and antimicrobial stewardship concerns 2, 1

Treatment Duration

• Limit treatment to the shortest effective course: generally no longer than 7 days for uncomplicated cystitis 1
• Three-day courses are adequate for TMP-SMX if susceptible 7, 6
• Five-day courses for nitrofurantoin 1, 3

Special Clinical Scenarios

If Patient Requests Immediate Treatment Before Culture Results

• Consider patient-initiated (self-start) treatment in reliable patients who can obtain urine specimens before starting therapy and communicate effectively with their provider 2, 1
• Base empiric choice on prior culture data if available 2, 1

If Symptoms Persist Despite Treatment

• Repeat urine culture to assess for ongoing bacteriuria before prescribing additional antibiotics 2
• Consider that nitrofurantoin resistance, if present, decays quickly, making it suitable for re-treatment 2

For Postmenopausal Women

• Consider vaginal estrogen therapy with or without lactobacillus-containing probiotics as adjunctive therapy, particularly if recurrent infections develop 2, 1, 7

Critical Antimicrobial Stewardship Principles

• Do not treat asymptomatic bacteriuria in non-pregnant patients, as this fosters antimicrobial resistance and increases recurrent UTI episodes 2, 1
• Avoid classifying uncomplicated UTI as "complicated" unless structural/functional urinary tract abnormalities, immunosuppression, or pregnancy are present, as this leads to unnecessary broad-spectrum antibiotic use 2
• Consider local antibiogram patterns, patient allergies, prior organism susceptibility, and cost when selecting antibiotics 2, 1

Common Pitfalls to Avoid

• Do not use fluoroquinolones empirically for simple cystitis given their broad spectrum and contribution to resistance 2, 1, 3
• Do not extend treatment beyond 7 days for uncomplicated lower UTI 1
• Do not obtain surveillance urine testing in asymptomatic patients after treatment 1
• Recognize that high rates of TMP-SMX and ciprofloxacin resistance in many communities preclude their empiric use, particularly in patients recently exposed to these agents 3

When to Consider Alternative Diagnosis

• If vaginal irritation or increased vaginal discharge is present with dysuria, consider vaginitis rather than UTI 2
• If fever or flank pain is present, this suggests pyelonephritis rather than simple cystitis and requires different management 2