Institution: | 1 Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America, , 2 Gen-Probe, San Diego, California, United States of America, , 3 Genomic Analysis Laboratory, The Salk Institute, La Jolla, California, United States of America, , 4 Department of Family/Preventive Medicine, University of California at San Diego School of Medicine, San Diego, California, United States of America |