Sensitivity of nPCR for four types of membrane protein DNA and of two pairs of primers for Tpp47 DNA of Treponema pallidum in whole blood of congenital syphilis newborns.

Background: Problems exist in congenital syphilis (CS) diagnosis and no single test can be used to diagnose CS. Objective: To know whether there exist differences of nested polymerase chain reaction (nPCR) sensitivity among four membrane protein DNA and of nPCR between two pairs of primers for Tpp47. Methods: We collected 30 CS patients as a study group, and 20 cases admitted to hospital for other reasons as a control group. The blood samples from newborns were left of blood for other examination, not special for the study. Following confirmed diagnosis, DNA was extracted from blood. nPCR examined for membrane protein DNA in both groups. Results: Sensitivity of nPCR for Tpp15, Tpp17, Tpp45, and Tpp47 (total) was 6/30, 3/30, 1/30, and 20/30, respectively. The sensitivity of nPCR for Tpp47 was highest among that of four types of membrane protein DNA. The nPCR sensitivity of two pairs of primers (a and b) for Tpp47 was 11/30 and 13/30, respectively. There was no significant difference between two pairs of primers for Tpp47, and total sensitivity of nPCR for Tpp47 combining Tpp47a with Tpp47b was up to 20/30. Conclusion: Sensitivity of nPCR for Tpp47 was highest among that of four types of membrane protein DNA. Two pairs of primers for Tpp47 different bands could elevate nPCR sensitivity.