Toxoplasma genotyping in congenital toxoplasmosis in Upper Egypt: evidence of type I strain

Abstract

Toxoplasma gondii has subpopulation structures in different geographical regions caused by less frequent sexual recombination, population sweeps, and biogeography. The majority of strains isolated in North America and Europe fall into one of three clonal lineages, referred to as types I, II, and III. So far, little is known about genetics of Toxoplasma strains in Africa. The present study aimed to determine the genotype of Toxoplasma strains obtained directly from trophoblastic/placental tissues of 29 complicated pregnant women using multilocus nested-PCR-RFLP technique depending on four independent genetic loci (5' SAG2 and 3' SAG2), SAG3, GRA6, and BTUB genes. All samples gave positive amplicons at 5'-3' SAG2 and SAG3 genes. Meanwhile, no amplification products were observed in 12 (41.37%) and 10 (34.48%) samples with GRA6 and BTUB genes, respectively. The restriction pattern revealed the presence of genotype I in all samples, except one sample, which revealed atypical genotype with unusual restriction pattern at 3' SAG2 gene. The negative amplifications in some samples could be due to presence of mutations or polymorphisms in the primer binding sites of these isolates, raising the possibility of mixed or recombinant genotypes. To the best of our knowledge, this is the first time to perform genotype analysis study based on Multiplex nPCR-RFLP technique for genetic characterization of T. gondii in Egypt. Besides, it is the first time to prove that the most prevalent strain of T. gondii, responsible for congenital toxoplasmosis in Upper Egypt, is the highly virulent type I. Atypical genotype was detected as well.

Seroprevalence, isolation, molecular detection and genetic diversity of Toxoplasma gondii from small ruminants in Egypt

“…The negative amplifications in two samples could be because of presence of mutations or may be due to polymorphisms in the primer binding locations of these isolates, raising the likelihood of recombinant or mixed genotypes as affirmed by Eldeek et al (2017).…”

Seroprevalence and Genetic Characterization of Toxoplasma gondii among Children with Neurodevelopmental Disorders in Egypt

“…Nassef et al [ 45 ] detected Toxoplasma genotype I in 34.6% of PCR-positive samples from pregnant females with obstetric complications using nested PCR-RFLP at the SAG2 locus. Additionally, there was a predominance of genotype I in a study done by Eldeek et al [ 40 ] from females with complicated pregnancies using multilocus RFLP analysis. In contrast to our findings, type II (87%) and type I (13%) were isolated from cases with abortion and intrauterine fetal death using nested PCR-RFLP for the SAG2 gene [ 46 ].…”

“…About 12% positivity rate of Toxoplasma using nested PCR of GRA6 gene was documented in another study in Egypt [ 39 ]. However, Eldeek et al [ 40 ] recorded a higher prevalence rate of T. gondii (58.6%) using nested PCR of the same coding region.…”

An African perspective on the genetic diversity of Toxoplasma gondii: A systematic review

“…A possible connection between specific T. gondii genotype and congenital toxoplasmosis as well as ocular toxoplasmosis is seen in this review. There have been reports on severe or complicated cases of congenital toxoplasmosis linked to infections with type I, atypical and recombinant I/III or I/II strains (Boughattas et al, 2010(Boughattas et al, , 2011a(Boughattas et al, , 2011bDelhaes et al, 2010;Eldeek et al, 2017). The main factor for the severity of congenital toxoplasmosis is the stage of pregnancy at the time of infection; infection in early pregnancy has more severe consequences than infection late in pregnancy (Ajzenberg et al, 2002).…”

“…In contrast, type I was predominant in the congenital-related group. This group included isolates from studies where the study population consisted of pregnant women, women with terminated pregnancies and cases of congenital toxoplasmosis or infants (Boughattas et al ., 2010 , 2011 a , 2011 b ; Tolba et al ., 2014 ; Nassef et al ., 2015 ; Badr et al ., 2016 ; Eldeek et al ., 2017 ; Lahmar et al ., 2020 ; Nzelu et al ., 2021 ). Type I was also the dominant genotype in cases involving ocular toxoplasmosis (Tolba et al ., 2014 ; Ali et al ., 2018 ).…”