1. Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow, G4 0RE, UK
2. Villanova University, 800 Lancaster Avenue, Villanova, PA 19026, USA
3. Department of Microbiology and Immunology, Columbia University, 701 W. 168 St., HHSC 1208, New York, NY 10032, USA