Investigation of toxoplasma gondii by PCR method in amniocentesi̇s fluid of pregnant women with suspected toxoplasmosis

Introduction and Aim: Toxoplasmosis is a parasitic infection caused by Toxoplasma gondii (T. gondii) that can affect all organs. Toxoplasmosis is extremely important in people with suppressed immune systems and in pregnant women, and it can cause congenital toxoplasmosis in pregnant women. The aim of this study is to screen T. gondii IgG and IgM antibodies in the serum of pregnant women by ELISA, to apply avidity test to patients with both positive/intermediate IgM and IgG values, and to investigate parasite DNA in amniotic fluid and serum samples by Real Time PCR. In addition, we aimed to determine the compatibility between ELISA tests used in toxoplasmosis screening in pregnant women and Real Time PCR results used in the diagnosis of congenital toxoplasmosis. Material and Methods: Maternal blood and amniotic fluid samples were collected at the perinatology clinics of Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Gynecology and Obstetrics, and Sakarya University Training and Research Hospital, Department of Gynecology and Obstetrics, between June 2022 and May 2024. T. gondii IgM and IgG antibodies were investigated in maternal serum samples by ELISA. Avidity test was performed to serums with IgG and IgM positivity. DNA was extracted from serum and amniotic fluid samples and the presence of T. gondii DNA was investigated using the Real Time PCR. Results: The average age of the pregnant women participating in the study was 32.05±6.12 and 76.32% of the patients were between 13-19th gestational weeks. Of the 38 pregnant women, four (10.52%) were IgM positive, one (2.63%) was intermediate, and 33 (86.85%) were negative. Of the 38 pregnant women whose T. gondii IgG antibody was investigated by ELISA, 16 (42.11%) were positive and 22 (57.89%) were negative. Low avidity was detected in three pregnant women. Using the Real Time PCR, no T. gondii DNA was detected both in the amniotic fluid and maternal serum samples. Conclusion: In our study, no PCR positivity was found even in pregnant women who had acute toxoplasmosis. In patients with acute toxoplasmosis, IgM antibodies can remain positive in the serum for a long time and low avidity results can be detected for as long as one year. Therefore, we can suggest that PCR testing from amniotic fluid is a reliable method in the prenatal diagnosis of congenital toxoplasmosis when supported by clinical findings and ultrasound, in addition to serological screening tests performed in pregnant women.