Detection of SPM-1-producing Pseudomonas aeruginosa and class D β-lactamase-producing Acinetobacter baumannii isolates by use of liquid chromatography-mass spectrometry and matrix-assisted laser desorption ionization-time of flight mass spectrometry.

This study evaluates the accuracy of liquid chromatography-mass spectrometry (LC-MS) and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) for detecting carbapenem hydrolytic activity among SPM-1-, GIM-1-, and GES-5-producing Pseudomonas aeruginosa isolates and OXA-143-, IMP-10-, and OXA-58-producing Acinetobacter baumannii isolates. Class A and B carbapenemase activities were rapidly detected by MALDI-TOF in a 2-h assay. However, an extended incubation time was necessary for detection of carbapenem-hydrolyzing class D β-lactamase (CHDL) activity in Acinetobacter spp.