A convenient method to screen for carbapenemase-producing Pseudomonas aeruginosa

A combined-disk method using imipenem and cloxacillin was evaluated to discriminate between carbapenemase-producing (n = 56) and nonproducing (n = 62) strains of Pseudomonas aeruginosa. With a cloxacillin load of 4,000 μg/disk, this very simple method showed a sensitivity and a specificity of 100%, irrespective of the type of carbapenemase produced.