1. Unit of Bioengineering and Mass Spectrometry Unit, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium, and Laboratory of Microbial Interactions, Department of Molecular and Cellular Interactions, Flanders Interuniversity Institute for Biotechnology (VIB), Vrije Universiteit Brussel, 1050 Brussels, Belgium