[1] City Hosp Sunderland NHS Trust, Sunderland SR4 7TP, England
[2] Cent Publ Hlth Lab, London NW9 5DF, England
[3] Univ Wales Hosp, Dept Med Microbiol, Anaerobe Reference Unit, Cardiff CF14 4XN, S Glam, Wales
[4] Univ Wales Hosp, PHLS, Cardiff CF14 4XN, S Glam, Wales
[5] Publ Hlth Lab Serv, Ctr Communicable Dis Surveillance, Div Healthcare Associated Infect & Antimicrobial, London NW9 5EQ, England
[6] Univ Durham, Wolfson Res Inst, CDSC N E, Stockton On Tees TS17 6BH, England
[7] Newcastle Publ Hlth Lab, Inst Pathol, Newcastle Upon Tyne NE4 6BE, Tyne & Wear, England
[8] Freeman Rd Hosp, Newcastle Upon Tyne NE7 7DN, Tyne & Wear, England
[9] Bristol Publ Hlth Lab, Bristol BS2 8EL, Avon, England
[10] Gen Infirm, Leeds LS1 3EX, W Yorkshire, England
[11] Univ Leeds, Old Med Sch, Leeds LS1 3EX, W Yorkshire, England