Affiliation: | Erfelijkheidsleer en Microbiologie, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussel, Belgium.; Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, the Netherlands. |