What are the recommended IV (intravenous) antibiotic regimens for pneumonia and urinary tract infections (UTI)?

Recommended IV Antibiotic Regimens for Pneumonia and UTI

For optimal patient outcomes, IV antibiotics for pneumonia and UTI should be selected based on infection severity, risk factors for resistant organisms, and local resistance patterns, with specific regimens tailored to the most likely pathogens.

Pneumonia Treatment

Hospital-Acquired Pneumonia (HAP)

Risk Stratification for HAP:

• For patients not at high risk of mortality and no MRSA risk factors: Use one of the following 1:

  • Piperacillin-tazobactam 4.5 g IV q6h
  • Cefepime 2 g IV q8h
  • Levofloxacin 750 mg IV daily
  • Imipenem 500 mg IV q6h
  • Meropenem 1 g IV q8h

• For patients not at high risk of mortality but with MRSA risk factors: Use one of the above options plus MRSA coverage 1

• For patients at high risk of mortality or with recent antibiotic use: Use two of the following (avoid using two β-lactams) 1:

  • Piperacillin-tazobactam 4.5 g IV q6h
  • Cefepime or ceftazidime 2 g IV q8h
  • Levofloxacin 750 mg IV daily
  • Ciprofloxacin 400 mg IV q8h
  • Imipenem 500 mg IV q6h
  • Meropenem 1 g IV q8h
  • Aminoglycoside (amikacin, gentamicin, or tobramycin)
  • Aztreonam 2 g IV q8h

  Plus MRSA coverage with:

  • Vancomycin 15 mg/kg IV q8-12h (target trough 15-20 mg/mL)
  • OR Linezolid 600 mg IV q12h

Community-Acquired Pneumonia (CAP)

For severe CAP requiring ICU admission:

• Without P. aeruginosa risk: Non-antipseudomonal 3rd generation cephalosporin plus macrolide OR moxifloxacin/levofloxacin ± cephalosporin 1

• With P. aeruginosa risk: Antipseudomonal cephalosporin OR acylureidopenicillin/β-lactamase inhibitor OR carbapenem PLUS ciprofloxacin OR macrolide + aminoglycoside 1

For specific pathogens:

• S. pneumoniae: Penicillin G (if MIC <2), ceftriaxone, or high-dose amoxicillin 1

  • Ceftriaxone 1 g daily is as effective as 2 g daily for CAP 2

• MSSA: Oxacillin, cefazolin, or flucloxacillin 1

• MRSA: Vancomycin, teicoplanin, or linezolid 1

• Atypical pathogens (Mycoplasma, Chlamydophila):

  • Azithromycin (500 mg day 1, then 250 mg daily) for 3-5 days 3, 4
  • Doxycycline or fluoroquinolones are alternatives 1

• Legionella: Levofloxacin 750 mg IV daily or moxifloxacin 400 mg IV daily 1

Duration of Therapy for Pneumonia:

• Generally 5-8 days for responding patients 1
• Switch to oral therapy when clinically stable 1

Urinary Tract Infection Treatment

For complicated UTI and pyelonephritis:

• Cefepime: 1-2 g IV every 12 hours for 7-10 days 5
• Alternatives: Levofloxacin, ciprofloxacin, aminoglycosides, carbapenems 5

For UTI with specific pathogens:

• E. coli, K. pneumoniae (severe): Cefepime 2 g IV q12h for 10 days 5
• E. coli, K. pneumoniae, P. mirabilis (mild to moderate): Cefepime 0.5-1 g IV q12h for 7-10 days 5

Important Clinical Considerations

Risk factors requiring MRSA coverage:

• Prior IV antibiotics within 90 days
• Hospitalization in unit where >20% of S. aureus is MRSA
• Unknown MRSA prevalence
• High mortality risk (ventilatory support, septic shock) 1

Criteria for IV to oral switch:

• Clinical stability (temperature ≤37.8°C, heart rate ≤100/min, respiratory rate ≤24/min, SBP ≥90 mmHg, O2 saturation ≥90%, normal mental status) 1
• Ability to maintain oral intake 1

Common pitfalls to avoid:

• Overuse of broad-spectrum antibiotics: Use targeted therapy based on local resistance patterns 1
• Inadequate MRSA coverage when risk factors present 1
• Prolonged IV therapy: Switch to oral when clinically stable 1
• Inadequate dosing: Ensure appropriate dosing for renal function 5
• Monotherapy for P. aeruginosa: Consider combination therapy initially 1

Special considerations:

• For aspiration pneumonia: β-lactam/β-lactamase inhibitor or clindamycin + cephalosporin 1
• Adjust dosing in renal impairment according to creatinine clearance 5
• Consider local antibiogram when selecting empiric therapy 1