Rapid Multiplex Antimicrobial Resistance Profiling and Bacterial Identification by LAP‐MALDI Mass Spectrometry Biotyping

ABSTRACT

Rapid and accurate characterization of antimicrobial resistance is essential for effective patient treatment and outcomes. Infection‐causing microorganisms often harbour multi‐drug resistance, requiring multiple tests for identification. Here, we present a multiplex functional assay using liquid atmospheric pressure (LAP) matrix‐assisted laser desorption/ionization (MALDI) as next‐generation MALDI biotyping technology, which can accurately determine antibiotic resistance/susceptibility within three hours from <5 µL of bacterial culture, employing a beta‐lactam antibiotic panel. Strains with common resistance genes, including OXA‐48, KPC‐3, and VIM‐1, as well as susceptible isolates, are easily and reliably classified. Concurrent with multi‐drug testing, the same bacterial sample provides species‐identifying lipid and protein profiles (up to 100% classification accuracy) and characterization through tandem mass spectrometry (MS/MS) protein sequencing, facilitated by LAP‐MALDI's ability to generate multiply charged protein ions. Detection of multiple antibiotics, their degradation products and lipids/proteins with high mass accuracy, along with the possibility of protein sequencing, offers new diagnostic possibilities for clinical microbiology and antimicrobial stewardship that are less probability‐based than conventional MALDI biotyping.