1. Department
of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands
2. Institute
for Microbiology, Ernst-Moritz-Arndt-University Greifswald, Greifswald 17489, Germany
3. Center
for Dentistry and Oral Hygiene, Department of Periodontology, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands
4. Department
of Molecular Genetics, University of Groningen, Groningen 9700 AB, The Netherlands