1. Department of Obstetrics and Gynecology, University of Washington, Box 356460, Seattle, WA 98195-6460, USA
2. Center for Microbiology Research, Kenya Medical Research Institute, Kenya
3. Department of Medical Microbiology, University of Nairobi, Nairobi, Kenya
4. Department of Obstetrics and Gynecology, Oregon Health Sciences University, Portland, OR, USA
5. Department of Medicine, University of Washington, WA, USA