A New Specimen for Syphilis Diagnosis: Evidence by High Loads of Treponema pallidum DNA in Saliva

Abstract Background DNA from many pathogens can be detected in saliva. However, the presence and quantity of Treponema pallidum DNA in patients with syphilis in saliva is unknown. Methods 234 patients with syphilis with different stages and 30 volunteers were enrolled. Paired saliva and plasma samples were collected from all participants. Consecutive saliva samples from 9 patients were collected every 4 hours following treatment. Treponema pallidum DNA in samples was determined by nested polymerase chain reaction (PCR) and droplet digital PCR targeting polA and Tpp47. Results Treponema pallidum DNA detection rates in saliva and plasma were 31.0% (9/29) and 51.7% (15/29) in primary syphilis (P = .11), 87.5% (63/72) and 61.1% (44/72) in secondary syphilis (P