What antibiotics have Pseudomonas coverage?

Antibiotics with Pseudomonas Coverage

The recommended antibiotics with Pseudomonas coverage include antipseudomonal β-lactams (piperacillin-tazobactam, cefepime, ceftazidime, meropenem, imipenem), fluoroquinolones (ciprofloxacin, levofloxacin), aminoglycosides (amikacin, gentamicin, tobramycin), monobactams (aztreonam), and polymyxins (colistin). 1

Antipseudomonal β-lactams

• Penicillins

  • Piperacillin-tazobactam (3.375g IV q6h or 4.5g IV q6h) 1
  • Ticarcillin-clavulanic acid (3.1g IV q6h) 1

• Cephalosporins

  • Ceftazidime (2g IV q8h) 1
  • Cefepime (2g IV q8-12h) 1

• Carbapenems

  • Meropenem (1g IV q8h) 1
  • Imipenem/cilastatin (500mg IV q6h or 1g IV q8h) 1
  • Doripenem (500mg IV q8h) 1

Fluoroquinolones

• Ciprofloxacin (400mg IV q12h or 750mg PO q12h) 1
• Levofloxacin (750mg IV/PO q24h) 1, 2

Aminoglycosides

• Amikacin (15-20mg/kg IV q24h) 1
• Gentamicin (5-7mg/kg IV q24h) 1
• Tobramycin (5-7mg/kg IV q24h) 1

Monobactams

• Aztreonam (1-2g IV q6-8h) 1

Treatment Strategies for Pseudomonas Infections

Mild to Moderate Infections

For mild to moderate Pseudomonas infections, monotherapy with an antipseudomonal agent may be sufficient:

• Ciprofloxacin (oral or IV)
• Levofloxacin (750mg dose)
• Antipseudomonal β-lactam

Severe Infections

For severe Pseudomonas infections, combination therapy is recommended to increase the likelihood of appropriate initial coverage and prevent resistance development 3, 1:

1. Preferred combination regimens:

   • Antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus either ciprofloxacin or levofloxacin (750-mg dose)
   • Antipseudomonal β-lactam plus an aminoglycoside and azithromycin
   • Antipseudomonal β-lactam plus an aminoglycoside and an antipneumococcal fluoroquinolone 3

2. For penicillin-allergic patients:

   • Substitute aztreonam for the β-lactam component 3

Special Considerations

• Pseudomonas pneumonia: The IDSA/ATS guidelines recommend combination therapy for at least 48 hours or until diagnostic test results are known 3

• Cystic fibrosis patients: May require higher doses and consideration of nebulized antibiotics (especially colistin, tobramycin) 1, 4

• Diabetic foot infections: Pseudomonas is rare in community-acquired infections and should only be covered empirically in life-threatening infections or settings with high prevalence of Pseudomonal infections 3

Evidence Quality and Clinical Implications

The recommendation for combination therapy in severe Pseudomonas infections is supported by multiple studies showing:

1. Better survival rates in immunocompromised hosts 5
2. Faster killing, less regrowth, and decreased development of resistance with β-lactam plus aminoglycoside combinations 6
3. Synergistic activity between β-lactams and aminoglycosides or fluoroquinolones 7, 6

While both aminoglycoside and fluoroquinolone combinations with β-lactams show synergy, the β-lactam plus aminoglycoside combinations demonstrate faster killing and better prevention of resistance development 6.

Common Pitfalls and Caveats

1. Resistance development: P. aeruginosa can rapidly develop resistance during therapy. Combination therapy reduces this risk 5.

2. Aminoglycoside toxicity: Monitor renal function closely when using aminoglycosides 1.

3. Fluoroquinolone resistance: Due to increasing resistance of E. coli to fluoroquinolones, local susceptibility patterns should be reviewed before using these agents 3.

4. Pseudomonas identification: Visual cues (like "green tinge" of discharge) have only moderate predictive value for Pseudomonas infection 3.

5. Appropriate cultures: Obtain deep tissue cultures rather than surface swabs to guide targeted therapy, especially in chronic infections 3.

By selecting appropriate antipseudomonal agents and using combination therapy for severe infections, clinicians can optimize outcomes in patients with Pseudomonas infections while minimizing the development of resistance.