1. Department of Genitourinary Medicine, The Mortimer Market Centre, Camden PCT, London WC1E 6AU, UK
2. Clinical Microbiology, Chlamydia Laboratory, University College London Hospital, The Windeyer Institute of Medical Sciences, London W1T 4JF, UK
3. Centre for Sexual Health and HIV Research, University College, London WC1E 6JB, UK
4. The Department of HIV and STIs, Health Protection Agency, Centre for Infections, London NW9 5EQ, UK
5. Sexually Transmitted Bacteria Reference Laboratory, Health Protection Agency Centre for Infections, London NW9 5HT, UK