Identification of the OXA-48 carbapenemase family by use of tryptic peptides and liquid chromatography-tandem mass spectrometry

Jeffrey R. Strich, Honghui Wang, Ousmane H. Cissé, Jung Ho Youn, Steven K. Drake, Yong Chen, Avi Z. Rosenberg, Marjan Gucek, Patrick T. McGann, John P. Dekker, Anthony F. Suffredini

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Phenotypic detection of the OXA-48-type class D β-lactamases in Enterobacteriaceae is challenging. We describe a rapid (less than 90 min) assay for the identification of OXA-48 family carbapenemases in subcultured bacterial isolates based on a genoproteomic approach. Following in silico trypsin digestion to ascertain theoretical core peptides common to the OXA-48 family, liquid chromatography-tandem mass spectrometry (LC-MS/MS) data-dependent acquisition was used to identify candidate peptide markers. Two peptides were selected based on performance characteristics: ANQAFLPASTFK, a core peptide common to all 12 OXA-48 family β-lactamase members, and YSVVPVYQEFAR, a highly specific peptide common to 11 of 12 OXA-48 family proteins providing the basis for an LC-MS/MS multiple reaction monitoring assay. An accuracy assessment was performed that included 98 isolates, 26 of which were OXA-48 positive. Two additional specificity assessments were performed including a mixture of isolates positive for OXA-48, KPC, NDM, VIM, and IMP carbapenemases. A combination of expert rules and expert judgment was applied by blinded operators to identify positive isolates. All isolates containing an OXA-48 family carbapenemase across all three test sets were correctly identified with no false positives, demonstrating 100% sensitivity (95% confidence interval [CI], 91.2% to 100%) and 100% specificity (95% CI, 96.2% to 100%) for the assay. These findings provide a framework for an LC-MS/MS-based method for the direct detection of OXA-48 family carbapenemases from cultured isolates that may have utility in predicting carbapenem resistance and tracking hospital outbreaks of OXA-48-carrying organisms.

Original languageEnglish (US)
Article numbere01240-18
JournalJournal of clinical microbiology
Issue number5
StatePublished - May 2019


  • Carbapenemase
  • Genoproteomics
  • Mass spectrometry
  • OXA-48
  • Targeted proteomics

ASJC Scopus subject areas

  • Microbiology (medical)


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