Pre-Analytic Factors affecting Molecular tests for Congenital Syphilis

PROJECT SUMMARY Syphilis, caused by Treponema pallidum spp pallidum (T. pallidum), cases are rising at an alarming rate with devastating consequences for pregnant individuals and neonates. Syphilis in pregnancy carries a 21% increased risk for stillbirth, 6% increased risk for preterm delivery, and 9% increased risk for neonatal death. Some neonates with congenital syphilis manifest symptoms of disseminated infection before 2 years of age (early congenital syphilis) which carries a mortality rate of up to 38%. However, most neonates (60-90%) are asymptomatic at birth, and may develop symptoms of congenital syphilis later in life with risks for permanent damage to nervous, bone, eye, and musculoskeletal systems. There is currently no molecular diagnostic test for congenital syphilis in routine clinical use. Instead, indirect diagnosis of possible or probable infection relies heavily on neonatal serologic titer relative to maternal titer and maternal treatment history. Due to risks associated with a missed diagnosis of congenital syphilis and the lack of accurate diagnostics, treatment decisions are frequently subjective. There is a critical need for accurate, sensitive, and direct detection of syphilis infection to better inform diagnosis and treatment for congenital syphilis. Polymerase chain reaction (PCR)-based molecular tests have become routine for the detection of numerous infectious diseases due to the sensitivity and specificity of the technique. Sensitivity of PCR differs according to gene target, specimen type, and sampling technique. Despite attempts to develop PCR targeting regions of conserved genes like PolA and Tp47, no FDA approved syphilis PCR test exists. There is a gap in our understanding of the optimal sampling strategy for PCR as an adjunct to current algorithms for diagnosis of congenital syphilis and risk stratification, particularly in asymptomatic neonates. Therefore, we hypothesize that molecular PCR performance can be optimized by determining the best diagnostic specimen(s) for congenital syphilis in the context of maternal stage, treatment history and neonatal clinical evaluation. We have assembled a team to optimally address this hypothesis. Dr. Emily Adhikari is a maternal-fetal medicine specialist and Medical Director of Perinatal Infectious Diseases at Parkland Hospital where she supervises diagnosis and treatment of syphilis in pregnancy. In collaboration with neonatologist Dr. Shamaila Gill, and pediatric infectious disease specialist Dr. Amanda Evans, comprehensive neonatal diagnostic evaluation and clinical staging will be performed. Dr. Jeff SoRelle is trained in molecular genetic pathology and the requirements to clinically validate a test. He has developed several molecular tests including COVID-19 variants, which led him to collaborative efforts of the impact of Delta and Omicron variant infections in pregnancy with Dr. Adhikari resulting in publications in JAMA and Am J Obstet Gynecol. We propose the following aims: AIM 1: Determine whether PCR detects T. pallidum DNA in neonates exposed to maternal syphilis. AIM 2: Determine the best sample type and source for T. pallidum PCR.