Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America.|Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America.|Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America.|Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America.|Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America.|Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America.|Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America.|Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America.|Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America.