1. Center for Epidemiological Studies on HIV/AIDS & STI of Catalonia, ICO/Health Department, Generalitat de Catalunya, Badalona
2. CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona
3. Department of Preventive Medicine and Public Health, Universitat Autònoma de Barcelona
4. Microbiology Service, Hospital Universitari Germans Trias i Pujol
5. Sexual and Reproductive Health Center, CAP Sant Fèlix Sabadell
6. Youth Health Centre for Contraception and Sexuality, Barcelona
7. Sexual and Reproductive Health Center, BSA, Barcelona
8. Sexual and Reproductive Health Center Mataró-Maresme, Mataró, Spain