What is the recommended treatment for pyelonephritis?

Treatment for Pyelonephritis

Initial Management

Always obtain urine culture and susceptibility testing before initiating antibiotics in all patients with suspected pyelonephritis to guide definitive therapy. 1

• Empirical therapy must be tailored based on local fluoroquinolone resistance patterns and subsequently adjusted according to culture results 1
• The causative organism is predominantly Escherichia coli (75-95%), with occasional Proteus mirabilis and Klebsiella pneumoniae 1

Outpatient Treatment (Uncomplicated Cases)

When Local Fluoroquinolone Resistance is <10%

Oral ciprofloxacin 500 mg twice daily for 7 days is the first-line treatment. 1, 2

• Alternative once-daily fluoroquinolone options include:
  • Ciprofloxacin 1000 mg extended-release for 7 days 1
  • Levofloxacin 750 mg for 5 days 1, 3
• These regimens achieve 93-97% clinical cure rates 2

When Local Fluoroquinolone Resistance is ≥10%

Administer one initial intravenous dose of a long-acting parenteral antimicrobial (ceftriaxone 1g or aminoglycoside) before starting oral fluoroquinolone therapy. 1, 4

• This approach is critical because empiric fluoroquinolone monotherapy in high-resistance areas leads to treatment failure 1
• Resistance rates to ciprofloxacin have reached 48% in some populations, making this precaution essential 5

Alternative Oral Regimen

• Trimethoprim-sulfamethoxazole (TMP-SMX) 160/800 mg twice daily for 14 days is appropriate only if the uropathogen is documented as susceptible 1, 4
• Do not use TMP-SMX empirically due to high resistance rates (up to 55% for E. coli) 5

Inpatient Treatment (Complicated Cases or Severe Illness)

Initial intravenous therapy should include fluoroquinolone, aminoglycoside with or without ampicillin, extended-spectrum cephalosporin or extended-spectrum penicillin with or without aminoglycoside, or carbapenem. 1

• Ceftriaxone demonstrated superior microbiological eradication (68.7%) compared to levofloxacin (21.4%) in one recent trial, though clinical cure rates were similar 5
• Aminoglycosides can be dosed as gentamicin 5-7 mg/kg once daily 1
• Selection must be based on local resistance patterns and adjusted per culture results 1

Indications for Hospitalization

• Severe illness or inability to tolerate oral therapy 4
• Suspected complications (obstruction, abscess) 6
• Pregnancy (significantly elevated risk of severe complications) 4
• Sepsis or risk of multidrug-resistant organisms 4

Treatment Duration

Duration varies by antibiotic class:

• Fluoroquinolones: 5-7 days 1, 2
• TMP-SMX: 14 days 1
• β-lactams: 10-14 days 1

Oral Step-Down Therapy

• Oral β-lactams are less effective than fluoroquinolones or TMP-SMX but can be used if the pathogen is susceptible 1
• Do not use oral β-lactams as monotherapy without an initial parenteral dose 1

Special Populations

• In elderly patients, monitor closely for adverse effects, particularly with aminoglycosides (nephrotoxicity, ototoxicity) and fluoroquinolones (neuropsychiatric disorders, tendon disorders, arrhythmias) 1, 7

Follow-Up and Treatment Failure

• Most patients respond within 48-72 hours 4
• If no improvement occurs, obtain imaging (contrast-enhanced CT) and repeat cultures while considering alternative diagnoses 6, 4
• If concurrent urinary tract obstruction is identified, pursue urgent urological decompression 4

Critical Pitfalls to Avoid

• Never start antibiotics without obtaining urine cultures first 1
• Never use fluoroquinolones empirically in areas with >10% resistance without adding an initial parenteral dose 1
• Never use oral β-lactams or TMP-SMX empirically due to high resistance rates 1, 5
• Never fail to adjust therapy based on culture results 1
• Never use inadequate treatment duration, especially with β-lactam agents 1
• Never ignore local antibiogram data when selecting empiric therapy 1