A Novel Lipid-Based MALDI-TOF Assay for the Rapid Detection of Colistin-Resistant <i>Enterobacter</i> Species
Richard D. Smith, Christi L. McElheny, Jerilyn R. Izac, Francesca M. Gardner, Courtney E. Chandler, David R. Goodlett, Yohei Doi, J. Kristie Johnson, Robert K. Ernst
Abstract
species and Klebsiella aerogenes without performing antimicrobial susceptibility testing. Typically, susceptibility testing requires an additional 24 to 48 h, while the MS assay described in this study allows for resistant identifications in under 1 h after initial culture. Identification using MALDI-TOF MS would save time and prevent inappropriate use of colistin. MALDI-TOF MS is an easy-to-use, readily available, robust diagnostic tool in clinical laboratories. Furthermore, this study highlights limitations of polymyxin susceptibility testing. Use of a killing assay best captures how colistin treats infection and is shown to be highly correlated with our MS assay; thus, the MS assay in this study effectively predicts how colistin would treat a patient's infection. Use of MALDI-TOF MS for accurate and early identification of antimicrobial resistance can improve antimicrobial stewardship and patient outcomes.