VALIDATION OF A REAL TIME PCR KIT PROTOTYPE FOR EARLY DIAGNOSIS OF CONGENITAL CHAGAS DISEASE IN A MULTICENTER FIELD STUDY

BENATAR, ALEJANDRO F.; SCHIJMAN, ALEJANDRO G.; ROJKIN F. ; SOSA ESTANI, S.

Buenos Aires

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

SAP, SAIC, SAB, SAIB, SAA, SAFE, SAPIS, otras

VALIDATION OF A REAL TIME PCR KIT PROTOTYPE FOR EARLY DIAGNOSIS OF CONGENITAL CHAGAS DISEASE IN A MULTICENTER FIELD STUDYBenatar, AF; Besuschio, SA; Bortolotti, S; Ramirez, JC; Cafferata, ML; Danesi E, Lopez Albizu C, Ciganda A ; Lara L; Agolti, G; Seu S; Uequìn V; Curet L; Adamo, EL; Black F; Lucero, H; Esteva, M, Bua, J, Longhi, Curto MdeA; S; Poeylaut-Palena A; Scollo, K; Althabe, F; Capriotti G, Rojkin F; Sosa Estani, S; Schijman AG.** En el libro de resúmenes figuran sólo los autores responsables del consorcio público privado por cuestiones de límite de autores, en el póster sí figuran todos los autores, que son los anteriormente mencionados. Congenital transmission of T. cruzi occurs in approximately 4% of newborns to infected mothers. Treatment with trypanocidal drugs has an effectivity close to 100%, so it is essential to provide an early diagnosis of infection. The low sensitivity of the current microhematocrit method (MH) determines that around 75% of the babies must return for confirmatory serological diagnosis 10 months after birth. In practice, many patients cannot complete the algorithm and remain without diagnosis. In this context, we developed a novel duplex Real Time PCR kit prototype, based on TaqMan probes, to improve sensitivity (Se) of early detection of congenital infection. Analytical Se of the prototype was 0.2 parasite equivalents/mL. The present work shows the prospective evaluation of the kit prototype in the framework of a multicenter field study. A total of 560 seropositive pregnant women were enrolled in five Health centers located in Buenos Aires, Chaco, Tucumán and Santiago del Estero, after written informed consent. Umbilical cord blood was collected at delivery and/or venous blood samples at 4-8 weeks of life to be analyzed blindly by PCR and MH. Additionally, venous samples were drawn at 10 months of life for final serodiagnosis. A total of 359 newborns got final diagnosis and 13 were infected, as detected by gold standard diagnosis. PCR was carried out on duplicates from each blood sample. It showed a Se of 66.7% and a specificity (Sp) of 95.2% from umbilical cord blood, and a Se of 63.6% and Sp of 98.9% in venous blood. Considering that samples had to be transported from the endemic areas to a core molecular biology laboratory for DNA extraction and PCR amplification (INGEBI), the prototype could detect a higher proportion of infected newborns than routine parasitological examination. It is expected that implementation of the PCR kit in trained centers located at the endemic areas may achieve a better performance and provide a more sensitive diagnosis.