Simultaneous Identification of Multiple β-Lactamases in Acinetobacter baumannii in Relation to Carbapenem and Ceftazidime Resistance, Using Liquid Chromatography-Tandem Mass Spectrometry.

Shotgun proteomics using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was applied to detect beta-lactamases in clinical Acinetobacter baumannii isolates. The correlation of the detection of beta-lactamase proteins (rather than PCR detection of the corresponding genes) with the resistance phenotypes demonstrated an added value for LC-MS/MS in antimicrobial susceptibility testing.