Figure 1.

Schematic diagram of the proposed workflow for combining lipid and protein MALDI-TOF MS analysis. For protein analysis, a colony is smeared on the target plate and overlaid with matrix. For analysis of lipid A, heat-inactivated microorganisms are submitted to mild-acid hydrolysis and the membranes resulting from this treatment are deposited on an adjacent position on the target plate, followed by matrix addition. Alternatively, for mycobacteria and filamentous fungi, heat-inactivated colonies are directly smeared on the target plate and overlaid with the appropriate matrix. The combined approach can yield species- and subspecies-level microbial identification and detect antibiotic resistance in one analysis.