Antipseudomonal

Antipseudomonal describes antimicrobial agents that are active against Pseudomonas aeruginosa, a non-fermenting Gram-negative bacterium known for intrinsic resistance and opportunistic infections. The term is used to categorize drugs with demonstrated activity against Pseudomonas, and it applies to several antibiotic classes. Examples include beta-lactams such as piperacillin, piperacillin-tazobactam, ticarcillin, ceftazidime, cefepime, imipenem, meropenem, doripenem, and aztreonam; fluoroquinolones like ciprofloxacin and levofloxacin; aminoglycosides such as gentamicin, tobramycin, and amikacin; and polymyxins such as colistin and polymyxin B. Ertapenem generally has limited or unreliable anti-pseudomonal activity. Susceptibility can vary by local resistance patterns.

In clinical practice, antipseudomonal agents are used to treat suspected or confirmed Pseudomonas infections, including hospital-acquired pneumonia, ventilator-associated pneumonia, bacteremia, intra-abdominal infections, urinary tract infections, wound infections, and in patients with cystic fibrosis who are chronically colonized. In severe infections or high-risk patients, combination therapy (for example, a beta-lactam with an aminoglycoside or fluoroquinolone) may be employed to broaden coverage or achieve synergistic effects, with de-escalation once susceptibilities are known. Dosing often considers organ function, drug penetration to the infection site, and local resistance data.

Resistance in Pseudomonas aeruginosa is multifactorial, involving reduced outer membrane permeability, efflux pumps, and beta-lactamase production. Susceptibility testing guides therapy, and antimicrobial stewardship aims to minimize resistance development. Adverse effects vary by drug class, including nephrotoxicity and ototoxicity with aminoglycosides and colistin-associated nephrotoxicity and neurotoxicity; seizures can occur with some beta-lactams at high doses.