1. Regional Lab for Public Health “Zeeland,” 4460 AA Goes,1 and
2. National Institute for Public Health and the Environment, 3720 BA Bilthoven,2 The Netherlands, and
3. Department of Clinical Chemistry, Microbiology and Immunology, University Hospital,3 and
4. Laboratory for Microbiology, University of Ghent,4 9000 Ghent, and
5. Department of Medical Microbiology, University Hospital UIA, Antwerp,5 Belgium