What is the treatment for urinary tract infections (UTIs)?

Treatment for Urinary Tract Infections

Uncomplicated Cystitis in Adults

For acute uncomplicated cystitis in women, use nitrofurantoin 100mg twice daily for 5 days as the preferred first-line agent, or alternatively trimethoprim-sulfamethoxazole (TMP-SMX) for 3 days if local resistance is documented to be <20%, or fosfomycin 3 grams as a single dose. 1, 2

• Nitrofurantoin is the drug of choice because it maintains consistently low resistance rates (approximately 2%) and causes minimal collateral damage to normal flora, making it superior for antimicrobial stewardship. 2

• TMP-SMX should only be used when your local antibiogram confirms resistance rates below 10-20%; above this threshold, treatment failures increase and empirical fluoroquinolone therapy becomes more cost-effective. 1, 3

• Fosfomycin offers the advantage of single-dose therapy with low resistance rates, making it ideal when medication compliance is a concern. 1, 2

• Avoid fluoroquinolones for uncomplicated cystitis as they should be reserved for more serious infections to prevent resistance development and collateral damage. 1, 4

Uncomplicated Pyelonephritis

For uncomplicated pyelonephritis, use oral fluoroquinolones (ciprofloxacin 500-750mg twice daily for 7 days or levofloxacin 750mg daily for 5 days) when local resistance is documented to be <10%. 2, 5

• In areas with higher fluoroquinolone resistance, initiate treatment with a single dose of parenteral ceftriaxone 1-2 grams IV, then transition to oral therapy based on culture results. 1, 2

• TMP-SMX or first-generation cephalosporins represent reasonable first-line oral agents when local resistance patterns support their use. 1

• Treatment duration is typically 7 days for fluoroquinolones and 10-14 days for beta-lactams. 1

Complicated UTIs

For complicated UTIs, treat for 7-14 days (14 days for men when prostatitis cannot be excluded), using empirical combination therapy with either amoxicillin plus an aminoglycoside, a second-generation cephalosporin plus an aminoglycoside, or an intravenous third-generation cephalosporin. 1, 2

Complicated UTIs occur in patients with:

• Urinary tract obstruction, foreign bodies (catheters), incomplete voiding, or vesicoureteral reflux 1

• Male sex, pregnancy, diabetes mellitus, or immunosuppression 1

• Recent instrumentation, healthcare-associated infections, or multidrug-resistant organisms 1

• Always obtain urine culture and susceptibility testing before initiating therapy, then tailor antibiotics based on results. 1

• The microbial spectrum is broader than uncomplicated UTIs, with E. coli, Proteus, Klebsiella, Pseudomonas, Serratia, and Enterococcus species commonly isolated. 1

• Address the underlying urological abnormality or complicating factor, as antibiotics alone may be insufficient without source control. 1, 2

• When the patient is hemodynamically stable and afebrile for at least 48 hours, consider shortening treatment to 7 days. 1

Catheter-Associated UTIs

For catheter-associated UTIs, remove or replace the catheter when feasible, obtain urine culture, and treat for 7-14 days based on culture results and clinical severity. 1

• Catheter-associated UTIs are the leading cause of secondary healthcare-associated bacteremia, with approximately 10% mortality. 1

• The incidence of bacteriuria increases 3-8% per day with indwelling catheterization, making duration the most important risk factor. 1

• Do not obtain urine cultures in asymptomatic catheterized patients, as bacteriuria is nearly universal and does not require treatment. 1

• Treat only when patients develop new fever, rigors, altered mental status, flank pain, costovertebral angle tenderness, acute hematuria, pelvic discomfort, or dysuria (in recently decatheterized patients). 1

Pediatric UTIs (Ages 2-24 Months)

For febrile infants and children 2-24 months with UTI, treat with oral or parenteral antimicrobials effective against common uropathogens for 7-14 days, adjusting therapy based on culture sensitivities. 1

• Obtain urine by catheterization or suprapubic aspiration for culture; bag-collected specimens are inadequate for diagnosis. 1

• A positive culture requires ≥50,000 CFU/mL of a uropathogen with urinalysis demonstrating bacteriuria or pyuria. 1

• Perform renal and bladder ultrasonography after confirming the first UTI to evaluate for anatomic abnormalities. 1

• Although ciprofloxacin is effective in pediatric patients, it is not first-choice due to increased incidence of joint and surrounding tissue adverse events compared to controls. 6

Asymptomatic Bacteriuria: When NOT to Treat

Do not treat asymptomatic bacteriuria in non-pregnant patients, as treatment provides no benefit and increases antimicrobial resistance. 1, 2

• The only two populations requiring treatment are pregnant patients and those undergoing invasive urologic procedures with expected mucosal bleeding. 2

• For pregnant patients with asymptomatic bacteriuria, treat for 3-5 days depending on the antimicrobial used. 2, 5

• Omit surveillance urine testing in asymptomatic patients with recurrent UTIs, as this leads to unnecessary treatment and antibiotic exposure. 1, 2

• Asymptomatic bacteriuria is common in older adults and institutionalized individuals but shows no benefit from treatment over placebo. 5

Recurrent UTIs (≥2 in 6 Months or ≥3 in 1 Year)

For recurrent UTIs, obtain urine culture with each symptomatic episode before initiating treatment, and use patient-initiated treatment protocols in select patients while awaiting culture results. 1, 2

• Use first-line therapy (nitrofurantoin, TMP-SMX, or fosfomycin) dependent on the local antibiogram and prior culture results. 1

• Treat acute episodes with as short a duration as reasonable, generally no longer than 7 days. 1

Prevention strategies:

• Vaginal estrogen therapy is strongly recommended for postmenopausal women and may significantly reduce infection frequency. 2, 5
• Methenamine hippurate reduces recurrent UTI episodes in women without urinary tract abnormalities. 2, 5
• Daily antibiotic prophylaxis with nitrofurantoin is most effective (reducing UTI rate to 0.4 per year) but should be balanced against antimicrobial stewardship concerns. 2
• Increased fluid intake may reduce recurrent UTI risk in premenopausal women. 2, 5
• Post-coital antibiotic prophylaxis within 2 hours of intercourse may be considered when infection patterns are clearly linked to sexual activity. 2

Antimicrobial Stewardship Principles

Deescalate antibiotics based on culture results whenever possible, and prefer oral regimens over intravenous therapy as they show comparable outcomes with reduced adverse events. 2, 5

• Multiple randomized trials demonstrate that all-oral or mostly-oral regimens result in comparable outcomes to IV-only treatment while reducing hospital length of stay and catheter-related complications. 2

• Use prior culture data when available to guide empiric therapy for acute episodes while awaiting new culture results. 2

• Obtain urine culture before initiating antibiotics in patients with recurrent UTIs to enable targeted therapy and track resistance patterns. 1, 2

Critical Pitfalls to Avoid

• Do not diagnose UTI based solely on positive urine culture without corresponding symptoms - this represents asymptomatic bacteriuria and should not be treated. 2

• Do not use broad-spectrum antibiotics for extended durations when narrower-spectrum agents are effective based on culture results. 2

• Do not prescribe fluoroquinolones empirically for uncomplicated cystitis when first-line agents are appropriate, as this accelerates resistance development. 2, 4

• For persistent symptoms despite treatment, obtain repeat urine culture before prescribing additional antibiotics rather than empirically escalating therapy. 2

• Ensure adequate source control (removing or changing catheters when feasible, addressing urological abnormalities) as antibiotics alone may be insufficient for complicated UTIs. 1, 2