Development of tip-desorption electrospray ionization coupled with ion mobility-mass spectrometry for fast screening of carbapenemase-producing bacteria

Abstract

Drug-resistant bacteria is posing one of the greatest threats to human health. Carbapenemase-producing (CP) bacteria are a group of emerging highly drug-resistant bacteria which cause serious health problem in worldwide. Rapid and reliable detection of CP-bacteria is essential for point-of-care therapy and rapid infection control. In this study, a high-throughput tip-desorption electrospray ionization (tip-DESI) with solid-substrate tip was developed to couple ion mobility-tandem mass spectrometry (IM-MS/MS) for rapid screening of CP-bacteria from clinical samples. Raw bacteria spiked with indicators (i.e., carbapenems) was directly loaded on disposable substrate tip that connected with high voltage, and a desorption spray was applied for desorption and ionization of analytes. The substrate materials and desorption/ionization modes were optimized in this study. CP bacteria were ambiguously identified by monitoring of characteristic IM drift time and MS/MS spectra of hydrolyzed and decarboxylated carbapenems. We demonstrated this method for direct detection CP-bacteria in complex samples, showing excellent analytical performances including good tolerance to complex matrices, reducing interferences, high specificity, good repeatability, high sensitivity, and high analytical speed. Furthermore, this method was also applied for fast screening of CP-bacteria from different clinical bacteria, showing the potential applications for fast and reliable detection of antibiotic resistance in clinics.