A revolution in the identification of pathogens in clinical laboratories.

In the management of bacterial infection, identification of the pathogen after growth remains essential, so that the most appropriate treatment can be proposed even before antibiotic susceptibility data are available. The strategy for most common pathogens requires Gram staining, simple tests (eg, determination of oxidase and catalase activity), and appropriate phenotypic tests that require commercial identification kits and/or automated systems. Altogether, identification of common pathogens requires at least several hours; in some circumstances, it requires several days. Alternatively, molecular methods can be used, but they remain time consuming and often expensive. A new proteomic strategy is about to change this strategy by identifying, within minutes, bacterial or fungal species grown on plates. Matrix–assisted laser desorption ionisation time-of-flight (MALDI-TOF) mass spectrometry can examine the profile of proteins detected directly from an intact bacterial cell surface. This technique,