1. Laboratory Services, Department of Public Health, Philadelphia, PA 19146, USA
2. Division of Microbiology, Department of Pathology and Laboratory Medicine, Hamad Medical Corporation, Doha P.O. Box 3050, Qatar
3. Division of Infectious Diseases, Communicable Diseases Centre, Hamad Medical Corporation, Doha P.O. Box 3050, Qatar
4. Biomedical Research Centre, Qatar University, Doha P.O. Box 2713, Qatar