1. Institute for Infectious Diseases, University of Bern, Bern, Switzerland
2. Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
3. Ambulatorium Kanonengasse, Zurich, Switzerland
4. Laborgemeinschaft 1, Zurich, Switzerland
5. WHO Collaborating Centre for Gonorrhoea and Other STIs, Örebro University, Örebro, Sweden