1. Division of Microbiological Studies, Food and Drug Administration, Washington, D.C. 202041;
2. Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 208142;
3. INOVA Fairfax Hospital, Falls Church, Virginia 220423;
4. Escherichia coli Reference Center, Pennsylvania State University, University Park, Pennsylvania 168024; and
5. Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan 606-015