Paterson used criteria to describe strains of Pseudomonas aeruginosa that are multidrug-resistant or panresistant.


Classes of antibiotics used to treat Pseudomonas aeruginosa:

(1) antipseudomonal cephalosporins

(2) antipseudomonal carbapenems

(3) combinations of beta-lactam with a beta-lactamase inhibitor

(4) antipseudomonal fluoroquinolones

(5) aminoglycosides


A strain of Pseudomonas aeruginosa is multidrug resistant if it shows decreased susceptibility to 2 or more of these classes of antibiotics.


Panresistance occurs when the strain shows diminished susceptibility to all of the antibiotics recommended for empirical therapy. For ventilator-associated pneumonia these would be:

(1) cefepime

(2) ceftazidime

(3) imipenem

(4) miropenem

(5) piperacillin-tazobactam

(6) ciprofloxacin

(7) levofloxacin


Additional resistance to colistin or polymyxin may mean that there are no treatment options for the patient.


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