Treatment of Pyelonephritis
For uncomplicated pyelonephritis in outpatients, oral ciprofloxacin 500 mg twice daily for 7 days or levofloxacin 750 mg once daily for 5 days is the first-line treatment when local fluoroquinolone resistance is below 10%. 1
Initial Diagnostic Steps
Before starting any antibiotic therapy:
- Obtain urine culture and susceptibility testing in all patients to guide definitive therapy and adjust empiric treatment based on results 1
- Blood cultures are unnecessary in uncomplicated cases but should be reserved for immunocompromised patients or those with uncertain diagnosis 2
Outpatient Treatment Algorithm
When Fluoroquinolone Resistance is <10%:
First-line oral options:
- Ciprofloxacin 500 mg twice daily for 7 days 1
- Ciprofloxacin 1000 mg extended-release once daily for 7 days 1
- Levofloxacin 750 mg once daily for 5 days 1, 3
When Fluoroquinolone Resistance is >10%:
Administer one dose of long-acting parenteral antibiotic first, then start oral therapy:
- Give ceftriaxone 1g IV once OR aminoglycoside (gentamicin 5-7 mg/kg) once 1
- Follow immediately with oral fluoroquinolone regimen 1
Alternative Oral Therapy (if pathogen susceptibility confirmed):
- Trimethoprim-sulfamethoxazole 160/800 mg (double-strength) twice daily for 14 days - only use if susceptibility confirmed, as resistance rates are high 1, 2
- Oral β-lactams for 10-14 days - less effective than fluoroquinolones and should not be used as monotherapy without initial parenteral dose 1
Inpatient Treatment
Indications for hospitalization:
- Severe illness or sepsis 1
- Persistent vomiting preventing oral intake 2
- Failed outpatient treatment 2
- Pregnancy 4
- Suspected complications 1
Initial IV antibiotic regimens:
- Fluoroquinolone (levofloxacin 750 mg IV daily) 1, 3
- Aminoglycoside with or without ampicillin (gentamicin 5-7 mg/kg once daily) 1
- Extended-spectrum cephalosporin (ceftriaxone 1g IV every 12-24 hours) 1, 5
- Extended-spectrum penicillin with or without aminoglycoside 1
- Carbapenem (for suspected multidrug-resistant organisms or extended-spectrum beta-lactamase producers) 1, 4
Treatment Duration by Antibiotic Class
- Fluoroquinolones: 5-7 days depending on specific agent 1
- Trimethoprim-sulfamethoxazole: 14 days 1
- β-lactams: 10-14 days 1
Resistance Patterns and Considerations
The microbial spectrum is predominantly Escherichia coli (75-95%), with occasional Proteus mirabilis and Klebsiella pneumoniae 1. Recent data shows concerning resistance trends:
- Fluoroquinolone resistance: approximately 10% in community settings, 18% in hospitals 6
- High resistance to trimethoprim-sulfamethoxazole (55% for E. coli) 5
- Rising resistance to third-generation cephalosporins (10% in hospitals as of 2012) 6
Tailor empiric therapy based on local resistance patterns and adjust according to culture results 1
Critical Pitfalls to Avoid
- Never start antibiotics without obtaining urine culture first 1
- Do not use fluoroquinolones empirically in areas with >10% resistance without adding initial parenteral dose 1
- Do not use oral β-lactams as monotherapy without initial parenteral dose 1
- Do not use trimethoprim-sulfamethoxazole or oral β-lactams empirically due to high resistance rates 7, 2
- Do not use inadequate treatment duration, especially with β-lactam agents 1
- Always adjust therapy based on culture results 1
Special Populations
- Elderly patients require close monitoring for adverse effects, particularly with aminoglycosides and fluoroquinolones 1
- Pregnant patients must be hospitalized and treated with parenteral therapy due to significantly elevated risk of severe complications 4