1. a Northern Ireland Public Health Laboratory, Department of Bacteriology , Belfast City Hospital , Belfast, Northern Ireland, UK
2. b Department of Pathogenic Biology , Xian Jiatong University , Xi'an, Shaanxi Province, The People's Republic of China
3. c Department of Haematology , Belfast City Hospital , Lisburn Road, Belfast, Northern Ireland, UK
4. d School of Biomedical Sciences , University of Ulster , Coleraine, Co. Londonderry, UK