Summary of a Workshop on the Clone Concept in the Epidemiology, Taxonomy, and Evolution of the Enterobacteriaceae and other Bacteria

Participants in this workshop included Mark Achtman, Max-Planck Institut ffir Molekulare Genetik, Berlin; Alan G. Barbour, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Rocky Mountain Laboratory, Hamilton, Mont; Michael Barile, US Food and Drug Administration, Bethesda, Md; Louis S. Baron, Walter Reed Army Institute of Research, Washington, DC; Mark Beaubien, Fogarty International Center, NIH; Thomas M. Buchanan, University of Washington, Seattle; B. Wesley Catlin, The Medical College of Wisconsin, Milwaukee; P. Patrick Cleary, University of Minnesota, Minneapolis; Mitchell L. Cohen, Center for Infectious Diseases, Centers for Disease Control (CDC), Atlanta; Alan S. Cross, Walter Reed Army Institute of Research; J. P. Duguid, University of Dundee Medical School, Scotland; Robert Edelman, NIAID; John J. Farmer, III, Center for Infectious Diseases, CDC; Samuel B. Formal, Walter Reed Army Institute of Research; Carl E. Frasch, US Food and Drug Administration; Peter Gemski, Walter Reed Army Institute of Research; Robert C. Goldman, National Institute of Arthritis, Diabetes, and Digestive and Kidney Diseases, NIH; Carolyn M. Hardegree, US Food and Drug Adminstration; James B. Kaper, University of Maryland School of Medicine, Baltimore; Dennis J. Kopecko, Walter Reed Army Institute of Research; Loretta Leive, National Institute of Arthritis, Diabetes, and Digestive and Kidney Diseases; Bruce R. Levin, University of Massachusetts, Amherst; Myron M. Levine, University of Maryland School of Medicine, Baltimore; Frits and Ida Orskov, International Escherichia and Klebsiella Centre, Statens Seruminstitut, Copenhagen; John B. Robbins, US Food and Drug Administration; Bernard Rowe, Central Public Health Laboratory, London; R. Bradley Sack, The Johns Hopkins University, Baltimore; J. C. Sadoff, Walter Reed Army Institute of Research; Rachel Schneerson, US Food and Drug Administration; Robert K. Selander, University of Rochester, New York; Richard Silver, US Food and Drug Administration; David H. Smith, University of Rochester, New York; Lucy S. Tompkins, University of Washington, Seattle; Kaye Wachsmuth, Center for Infectious Diseases, CDC; the late Lewis Wannamaker, University of Minnesota Medical School, Minneapolis; T. S. Whittam, University of Rochester, New York; Richard A. Wilson, Pennsylvania State Bethesda, Md. Investigators from Europe and the United States discussed epidemiologic, pathophysical, genetic, and evolutionary problems relating to the clone concept. T e workshop was opened by Dr Mark Beaubien, Acting Director of the Fogarty International Center, and by Dr Frits Orskov, who noted that Herbert John Webber first used the word clone in 1903 to designate a population in which all members have been derived from one and the same progenitor by nonsexual multiplication. For present purposes, the word clone will be used to denote bacterial cultures isolated independently from different sources, in different locations, and perhaps at different times, but showing so many identical phenotypic and genetic traits that the most likely explanation for this identity is a common origin. Dr Orskov pointed out that the concept of a clonal connection between isolates from a clear-cut outbreak of disease caused by a phenotypically well-characterized pathogen has probably always been accepted, even though the word "clone" itself may not have been used. In recent years, however, the clone concept has also been applied to bacteria (such as many serotypes of Escherichia coli) that usually do not cause clearcut outbreaks or epidemics. Dr Orskov concluded by expressing the hope that recently developed techniques would make it possible to characterize phenotypes within the many bacterial groups, thereby allowing a more precise definition of bacterial clones.