Use of polymerase chain reaction and rabbit infectivity testing to detect Treponema pallidum in amniotic fluid, fetal and neonatal sera, and cerebrospinal fluid

Abstract

The diagnosis of congenital syphilis continues to pose a difficult clinical challenge. Because the serodiagnosis of congenital syphilis has significant limitations, the direct detection of Treponema pallidum in suspect neonatal tissues or body fluids represents a desirable alternate diagnostic strategy. We developed and applied the polymerase chain reaction (PCR) for the detection of T. pallidum in clinical materials relevant to the diagnosis of congenital syphilis but which typically contain factors inhibitory for the PCR. Four methods of specimen processing were examined to circumvent PCR inhibition; clinical materials included amniotic fluids, neonatal sera, and neonatal cerebrospinal fluids. The PCR was 100% specific for T. pallidum compared with the sensitive rabbit infectivity test (RIT) for all clinical materials tested. For amniotic fluids, the PCR was 100% sensitive when correlated with the RIT but had a lesser sensitivity when applied to sera or cerebrospinal fluids, which typically contain few treponemes. The combined sensitivity of the PCR for all clinical samples was 78%. Positive PCR results also were obtained among some clinical specimens for which RIT was not performed; these results correlated well with either stigmata or risk factors for congenital syphilis. The combined results suggest that the PCR can be a useful adjunct to the diagnosis and clinical management of congenital syphilis and that it will provide a valuable tool for investigations of the pathogenesis of the disorder.

The Tprk Protein of Treponema pallidum Is Periplasmic and Is Not a Target of Opsonic Antibody or Protective Immunity

“…Lesion aspirates were obtained at designated time points for darkfield microscopy and, in experiment two, for PCR amplification and sequence analysis of the tprK gene. At the termination of experiment one (90 d after challenge), the spleens or popliteal nodes were excised for rabbit infectivity testing (RIT; reference 23). After the development of orchitis or seroconversion, recipient animals were killed and treponemes were harvested as described above.…”

Comparison of molecular and microscopic techniques for detection of Treponema pallidum in genital ulcers

“…The PCR has proven to be sensitive and specific in the laboratory diagnosis of a variety of infectious diseases, including syphilis (1,3,5,12,18,22,23). PCR amplification of T. pallidum DNA from serum, amniotic fluid, and cerebrospinal fluid has aided in the diagnosis of congenital syphilis (3,18) and neurosyphilis (5,11,12,18,23). The application of PCR in the diagnosis of syphilitic skin lesions has not been reported on as extensively.…”

“…These methodologies, particularly the PCR, have been used in the detection of treponemes. This technique has detected T. pallidum in a variety of clinical specimens, including serum (1,3,18), cerebrospinal fluid (1,3,5,12,18), amniotic fluid (1,3,18), fixed tissues (1), and lesion exudate (8,13,22). However, its performance relative to other tests, particularly in early disease, remains to be validated by extensive clinical studies.…”

Syphilis

“…The EIA tests has the advantage of being more objective and automated, requiring less work. PCR is most useful where the treponema serologic tests are limited: in primary, early congenital syphilis and neurosyphilis (15,(41)(42)(43)(44).…”