Molecular Typing of Treponema pallidum in Denmark: A Nationwide Study of Syphilis
Kirsten Salado-Rasmussen, Susan Cowan, Jan Gerstoft, Helle Kiellberg Larsen, Steen Hoffmann, Troels Bygum Knudsen, Terese Lea Katzenstein, Jørgen Skov Jensen
The aim of this nationwide study is to determine the strain type diversity among patients diagnosed with syphilis by PCR during a 4-year period in Denmark. Epidemiological data, including HIV status, for all patients were obtained from the Danish national syphilis registration system. Molecular strain typing was based on characterization of 3 variable treponemal genes, arp, tpr and tp0548. A total of 278 specimens from 269 patients were included. Among the fully typeable specimens (n = 197), 22 strain types were identified, with 1 type, 14d/g, accounting for 54%. The majority (93%) of the patients reported acquiring syphilis in Denmark. Among patients with concurrent HIV, 9 full strain types were identified and no difference in strain type was found by HIV status (p = 0.197). In conclusion, the majority of patients were infected in Denmark and the HIV-infected syphilis patients were diagnosed with a wide spectrum of different strain types of Treponema pallidum.