Treatment of Pseudomonas aeruginosa Infections

Comparative Effectiveness

• The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) suggests ceftolozane-tazobactam for difficult-to-treat CRPA (carbapenem-resistant Pseudomonas aeruginosa) infections when active in vitro 1

Treatment Algorithm Based on Infection Type

• For respiratory infections, ceftazidime-avibactam may be considered as an alternative to ceftolozane-tazobactam if resistance to ceftolozane-tazobactam is present 1, 2

Resistance Considerations

• Combination therapy may be considered for severe infections to prevent resistance development 3, 2
• Regular monitoring of susceptibility patterns is not explicitly cited, however, selection between these agents should ultimately be guided by in vitro susceptibility testing whenever possible 3, 2

Important Caveats

• Neither agent should be used as monotherapy for metallo-β-lactamase-producing strains, as these enzymes confer resistance to both drugs 1
• For non-severe or low-risk CRPA infections, older antibiotics that show in vitro activity may be considered for antibiotic stewardship purposes 1
• Local resistance patterns should influence the choice between these agents 2

Treatment of Carbapenem-Resistant Pseudomonas aeruginosa Infections

First-Line Treatment Options

• Newer β-lactam/β-lactamase inhibitor combinations, such as ceftolozane-tazobactam, ceftazidime-avibactam, and imipenem-relebactam, are preferred for non-Metallo-β-lactamase (Non-MBL) producing CRPA infections when susceptible 4

Treatment Based on Resistance Mechanism

• For severe infections caused by CRPA resistant to carbapenems and quinolones, combination therapy with intravenous amikacin/tobramycin or colistin plus a carbapenem/ceftazidime may be necessary, even with resistance, to provide synergy 5

Important Monitoring and Caveats

• Serum levels of aminoglycosides must be monitored closely in patients with cirrhosis to decrease the risk of renal failure, and renal function should be closely monitored during colistin and aminoglycoside therapy due to high nephrotoxicity risk 5

Special Considerations

• In patients with cirrhosis and CRPA infections, the risk of renal failure with nephrotoxic antibiotics must be carefully weighed against the benefits 5