A rapid diagnostic workflow for cefotaxime-resistant Escherichia coli and Klebsiella pneumoniae detection from blood cultures by MALDI-TOF mass spectrometry.

Nowadays, the global spread of resistance to oxyimino-cephalosporins in Enterobacteriaceae implies the need for novel diagnostics that can rapidly target resistant organisms from these bacterial species. In this study, we developed and evaluated a Direct Mass Spectrometry assay for Beta-Lactamase (D-MSBL) that allows direct identification of (oxyimino)cephalosporin-resistant Escherichia coli or Klebsiella pneumoniae from positive blood cultures (BCs), by using the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technology. The D-MSBL assay was performed on 93 E. coli or K. pneumoniae growing BC samples that were shortly co-incubated with cefotaxime (CTX) as the indicator cephalosporin. Susceptibility and resistance defining peaks from the samples' mass spectra were analyzed by a novel algorithm for bacterial organism classification. The D-MSBL assay allowed discrimination between E. coli and K. pneumoniae that were resistant or susceptible to CTX with a sensitivity of 86.8% and a specificity of 98.2%. The proposed algorithm-based D-MSBL assay, if integrated in the routine laboratory diagnostic workflow, may be useful to enhance the establishment of appropriate antibiotic therapy and to control the threat of oxyimino-cephalosporin resistance in hospital.

Citation

Elena De Carolis, Silvia Paoletti, Domenico Nagel, Antonietta Vella, Enrica Mello, Ivana Palucci, Giulia De Angelis, Tiziana D'Inzeo, Maurizio Sanguinetti, Brunella Posteraro, Teresa Spanu. A rapid diagnostic workflow for cefotaxime-resistant Escherichia coli and Klebsiella pneumoniae detection from blood cultures by MALDI-TOF mass spectrometry. PloS one. 2017;12(10):e0185935

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PMID: 28982134

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