1. Division of Medical Microbiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
2. Chulabhorn International College of Medicine, Thammasat University, Pathumthani, Thailand
3. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
4. Microbiology Laboratory, Johns Hopkins Hospital, Baltimore, Maryland, USA