What antibiotics (abx) with adult doses cover Pseudomonas in moderate to severe wounds?

Antibiotics Covering Pseudomonas in Moderate to Severe Wounds

For moderate to severe wounds requiring Pseudomonas coverage, use piperacillin-tazobactam 3.375g IV every 6 hours (or 4.5g IV every 6 hours for severe infections), or alternatively ceftazidime 2g IV every 8 hours, cefepime 2g IV every 8-12 hours, or meropenem 1g IV every 8 hours as first-line monotherapy. 1, 2

First-Line Antipseudomonal β-Lactams with Adult Dosing

Preferred Agents for Moderate to Severe Infections

• Piperacillin-tazobactam: 3.375g IV every 6 hours for moderate infections; increase to 4.5g IV every 6 hours for severe Pseudomonas infections 2

  • Achieves excellent tissue penetration in skin (34.8-94.2 mg/L), muscle (9.4-23.3 mg/L), and soft tissues 2
  • Widely distributed into wound tissues with mean concentrations 50-100% of plasma levels 2

• Ceftazidime: 2g IV every 8 hours (standard dosing); can escalate to maximum 6g daily in divided doses for severe infections 3, 1

  • For serious infections including bone/joint and complicated wounds: 2g IV every 8 hours 3
  • FDA-approved specifically for skin and soft tissue infections with Pseudomonas 3

• Cefepime: 2g IV every 8-12 hours 4, 1

  • Provides robust antipseudomonal coverage with good tissue penetration 1

• Meropenem: 1g IV every 8 hours 4, 1

  • Superior outcomes demonstrated in severe infections; can escalate to 2g IV every 8 hours for critically ill patients 1
  • Ranks among the most active agents globally against Pseudomonas 1

When to Add Combination Therapy

Add a second antipseudomonal agent (aminoglycoside or fluoroquinolone) for severe wounds with any of these features: 1

• Critically ill or septic shock patients 1
• Prior IV antibiotic use within 90 days 1
• Documented Pseudomonas on Gram stain 1
• Immunocompromised state 4
• High local prevalence of multidrug-resistant Pseudomonas 1

Second Agent Options for Combination Therapy

• Tobramycin: 5-7 mg/kg IV once daily (preferred aminoglycoside due to lower nephrotoxicity) 4, 1

  • Target peak levels 25-35 mg/mL 1
  • Requires therapeutic drug monitoring 1

• Amikacin: 15-20 mg/kg IV once daily 4, 1

  • Alternative aminoglycoside option 1

• Ciprofloxacin: 400mg IV every 12 hours (or 750mg PO twice daily for high-dose oral regimen) 4, 1

  • Less potent than aminoglycosides but useful alternative 1

Treatment Duration and Monitoring

• Standard duration: 7-14 days depending on wound severity and clinical response 1
• Continue antibiotics for 2 days after signs and symptoms of infection resolve, but longer therapy may be required for complicated infections 3
• De-escalate to monotherapy once susceptibility results are available if the patient is improving and organism is susceptible 1

Critical Pitfalls to Avoid

• Never assume all β-lactams cover Pseudomonas: Ceftriaxone, cefazolin, ampicillin-sulbactam, and ertapenem do NOT have antipseudomonal activity despite being broad-spectrum 1
• Avoid underdosing: Use maximum recommended doses for severe infections, as standard doses may be inadequate for Pseudomonas 1
• Do not use monotherapy for severe infections: Combination therapy delays resistance development and improves outcomes in critically ill patients 1, 5
• Monitor for nephrotoxicity and ototoxicity when using aminoglycosides; check drug levels, renal function, and auditory function 1

Special Considerations for Wound Infections

• Piperacillin-tazobactam achieves particularly good penetration into skin, muscle, and soft tissues, making it an excellent choice for wound infections 2
• For severe physiologic disturbance, advanced age, or immunocompromised patients with complicated infections, the Infectious Diseases Society of America recommends imipenem-cilastatin, meropenem, doripenem, or piperacillin-tazobactam as single agents 4
• Obtain wound cultures before starting antibiotics to confirm susceptibility and guide definitive therapy 4