1. Laboratory of Bacterial Pathogenesis, Kuzell Institute1 and Liposome Research Laboratory2, California Pacific Medical Center Research Institute, San Francisco, CA, USA 3Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 106 Dryden Hall, Corvallis, OR 97331-4804, USA 4Department of Microbiology, College of Sciences, Oregon State University, Corvallis, OR, USA