Unit of Microbiology, Belgian Nuclear Research Centre (SCK-CEN), Mol, Belgium.|Unit of Microbiology, Belgian Nuclear Research Centre (SCK-CEN), Mol, Belgium.|VIB Center for the Biology of Disease, VIB, Leuven, Belgium.|Unit of Microbiology, Belgian Nuclear Research Centre (SCK-CEN), Mol, Belgium. pieter.monsieurs@sckcen.be.