Direct detection of OXA-48-like carbapenemase variants with and without co-expression of an extended-spectrum β-lactamase from bacterial cell lysates using mass spectrometry

•LC-MS methods are used to identify intact OXA-48 like enzymes from bacterial lysates.•Individual protein variants of the OXA-48 like carbapenemases can be detected with tandem mass spectrometry.•OXA-48 like carbapenemases can be distinguished from extended spectrum β-lactamases like CTX-M-15.•The method for detection can be run in five minutes or less.