Detection of Treponema pallidum tpp47 DNA in clinical samples of syphilis patients.

BACKGROUNDS

To investigate the relationship between the presence of Treponema pallidum DNA in saliva, serum, and cerebrospinal fluid (CSF) in patients with different stages of syphilis.

PATIENTS AND METHODS

From 2020 to 2024, clinical samples, including saliva, serum, and CSF, were collected from 740 patients diagnosed with syphilis at the First Affiliated Hospital of Guangxi Medical University. Primer sequences targeting the Treponema pallidum gene tpp47 were designed for nested PCR (nPCR).

RESULTS

A total of 1023 samples were collected from 740 patients with syphilis, including 20 primary syphilis, 96 secondary syphilis, 90 neurosyphilis, and 534 latent syphilis. The overall detection rates of Treponema pallidum DNA in saliva, serum, and CSF were 13.6% (36/264), 3.1% (17/543), and 5.5% (12/216), and in secondary syphilis 40.0% (26/65), 3.4% (2/59), and 7.1% (1/14), all of which were significantly different (P < 0.001). The detection rates in secondary syphilis were 40.0% (26/65), 3.4% (2/59), and 7.1% (1/14), which were significantly different (P < 0.001) from those observed in the other categories. Notably, no significant discrepancies were observed between the three clinical samples from patients with primary, neurosyphilis, and latent syphilis (P > 0.05).

CONCLUSION

The Treponema pallidum DNA is most abundant in the saliva of syphilis patients, indicating a potential risk of saliva-mediated transmission of the disease.