1. Department of Periodontology and Oral Implantology and Oral Microbiology Testing Service Laboratory; Temple University School of Dentistry; Philadelphia PA USA
2. Department of Microbiology and Immunology; Temple University School of Medicine; Philadelphia PA USA
3. Department of Oral Microbiology; Center for Dentistry and Oral Hygiene; University Medical Center Groningen; University of Groningen; Groningen The Netherlands
4. Department of Medical Microbiology; University Medical Center Groningen; University of Groningen; Groningen The Netherlands