1. Division of Medical Microbiology, Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
2. Microbiology Laboratory, Johns Hopkins Hospital, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
3. Microbiology Laboratory, Suburban Hospital, Johns Hopkins Medical Institutions, Bethesda, Maryland, USA
4. Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA