1. Department of Microbiology and Immunobiology, School of Clinical Medicine, The Queen’s University of Belfast, Belfast BT12 6BN,1
2. School of Pharmacy, The Queen’s University of Belfast,2 and
3. Withers Orthopaedic Centre, Musgrave Park Hospital, Belfast BT9 7JB,3 United Kingdom
4. Department of Bacteriology, Belfast City Hospital,4 Belfast BT9 7BL, and