AIMS Congenital Toxoplasmosis (CT) in newborns results from primary maternal infection with T. gondii (TG). Most infected children show no symptoms at birth but are at great risk of sequelae during the first year of life or in early childhood [1]. Polymerase chain reaction (PCR) analysis of dried blood samples on the Guthrie card has been proposed as a sensitive method to screen for congenital CMV infection, but there are no data about the use for TG screening. The aim of present study was to assess the utility of PCR analysis of dried blood samples for the retrospective diagnosis of CT. METHODS A retrospective study was performed with 18 infants born between January 2010 and June 2012. Transmitters mothers seroconverted in the second trimester of pregnancy (mean 23.5 ± 7.9 weeks). At birth, serological tests (Enzygnost Toxoplasmosis IgG, IgM, IgA-Siemens Healthcare Diagnostics; Vidas Toxo IgMbioMerieux) as well as IgM-IgG WB (LDBio Toxoplasma WB IgG/IgM-LDBio Diagnostics) were performed in all mother-child pairs.Nucleic acids were extracted from Guthrie cards with VERSANT kPCR Sample Preparation system (Siemens) and Toxoplasma Q-PCR Alert Kit (Nanogen) was used for the amplification of TG target region AF 146527. RESULTS In 7/18 (38.9%) infants, CT was diagnosed by IgM-WB positivity at birth. The remaining 11 were considered non-infected (61.1%) and became IgG negative within 12 months of life. Infected infants received one-year therapy (pyrimethamine/sulfadiazine) and were followed according to our protocol. Four of these had a pathological neuroimaging (4/4 calcifications, 2/4 ventriculomegaly). None had hearing loss. TG DNA was detected in only one of the Guthrie cards of the infected newborns, while all the others were negative. CONCLUSIONS Although serological methods remain basic in the diagnosis of CT, TG DNA detection in Guthrie cards could be considered a retrospective method to evaluate infants (> 1 year of age) with clinical signs suggestive of CT. More studies with a larger number of infected cases are needed to assess the sensitivity of this method.
Capretti, M., Lanari, M., De Angelis, M., Marsico, C., Marangoni, A., Nardini, P., et al. (2012). TOXOPLASMA GONDII DNA DETECTION IN GUTHRIE CARDS: A RETROSPECTIVE STUDY. JOURNAL OF PEDIATRIC AND NEONATAL INDIVIDUALIZED MEDICINE, 1(1), 146-146 [10.7363/010106].
TOXOPLASMA GONDII DNA DETECTION IN GUTHRIE CARDS: A RETROSPECTIVE STUDY
MARANGONI, ANTONELLA;FOSCHI, CLAUDIO;FALDELLA, GIACOMO
2012
Abstract
AIMS Congenital Toxoplasmosis (CT) in newborns results from primary maternal infection with T. gondii (TG). Most infected children show no symptoms at birth but are at great risk of sequelae during the first year of life or in early childhood [1]. Polymerase chain reaction (PCR) analysis of dried blood samples on the Guthrie card has been proposed as a sensitive method to screen for congenital CMV infection, but there are no data about the use for TG screening. The aim of present study was to assess the utility of PCR analysis of dried blood samples for the retrospective diagnosis of CT. METHODS A retrospective study was performed with 18 infants born between January 2010 and June 2012. Transmitters mothers seroconverted in the second trimester of pregnancy (mean 23.5 ± 7.9 weeks). At birth, serological tests (Enzygnost Toxoplasmosis IgG, IgM, IgA-Siemens Healthcare Diagnostics; Vidas Toxo IgMbioMerieux) as well as IgM-IgG WB (LDBio Toxoplasma WB IgG/IgM-LDBio Diagnostics) were performed in all mother-child pairs.Nucleic acids were extracted from Guthrie cards with VERSANT kPCR Sample Preparation system (Siemens) and Toxoplasma Q-PCR Alert Kit (Nanogen) was used for the amplification of TG target region AF 146527. RESULTS In 7/18 (38.9%) infants, CT was diagnosed by IgM-WB positivity at birth. The remaining 11 were considered non-infected (61.1%) and became IgG negative within 12 months of life. Infected infants received one-year therapy (pyrimethamine/sulfadiazine) and were followed according to our protocol. Four of these had a pathological neuroimaging (4/4 calcifications, 2/4 ventriculomegaly). None had hearing loss. TG DNA was detected in only one of the Guthrie cards of the infected newborns, while all the others were negative. CONCLUSIONS Although serological methods remain basic in the diagnosis of CT, TG DNA detection in Guthrie cards could be considered a retrospective method to evaluate infants (> 1 year of age) with clinical signs suggestive of CT. More studies with a larger number of infected cases are needed to assess the sensitivity of this method.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
