Detection of polA gene in whole blood samples and preliminary observations with molecular subtyping of Treponema pallidum

Abstract

To detect Treponema pallidum (T.pallidum) DNA with polymerase chain reaction (PCR) in whole blood samples of syphilis patients and analyze their features of sub-genotypes. The clinical data of patients were collected from July 2012 to February 2013. And polA gene of syphilis was detected by PCR. The arp and tpr genes of polA gene-positive samples were analyzed by the established genotyping system.Statistical analyses were performed to compare different clinical courses and features to examine their correlations. The common treponemal gene target (polA) of 35 samples were detected in whole blood by PCR in 181 samples. A total of 24 cases (35.8%) were positive in 67 patients with newly diagnosed non-latent syphilis untreated patients;26 cases of latent syphilis were negative;7 cases (9.7%) were positive in 72 subsequent visit patients;4 cases (25.0%) were positive in 16 patients with sero-resistant. There were 4 subtypes of 14a (n = 7), 14b (n = 10), 13c (n = 4) and 14d (n = 14). Among those positive samples, there were 4 sero-resistant samples of 3 subtypes 14d and 1 subtype 14b. The feasibility of peripheral blood is confirmed. Although the positive rate of whole blood detection of T.pallidum gene is low, the method is both simple and reliable for patients with sero-resistant syphilis.