Abstract
1Department of Bacteriology, American Type Culture Collection, Rockville, Maryland 20852
2Department of Biology, University of Rochester, Rochester, New York 14627
3Department of Genetics and Development, University of Illinois, Urbana, Illinois 61801
4Meningitis and Special Pathogens Branch, Division of Bacterial Diseases, Center for Infectious Diseases, Centers for Disease Control, Atlanta, Georgia 30333