Genetic analysis of natural recombinant Brazilian Toxoplasma gondii strains by multilocus PCR–RFLP

Ferreira, Adriana de Melo; Vítor, Ricardo Wagner Almeida; Gazzinelli, Ricardo T.; Melo, Maria Norma

doi:10.1016/j.meegid.2004.12.004

Cited by 110 publications

(25 citation statements)

References 46 publications

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“…However, studies using multi-locus markers showed high genetic diversity in South American strains, which is absent in North American and European strains [3], [4]. Analysis of the isolates from domestic animals revealed four genotypes considered common clonal lineages in Brazil, BrI BrII, BrIII, and BrIV [5].…”

Section: Introductionmentioning

confidence: 99%

Overlapping Toxoplasma gondii Genotypes Circulating in Domestic Animals and Humans in Southeastern Brazil

et al. 2014

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Although several Toxoplasma gondii genotyping studies have been performed in Brazil, studies of isolates from animals in the state of Minas Gerais are rare. The objective of this study was to conduct a genotypic characterization of T. gondii isolates obtained from dogs, free-range chickens, and humans in Minas Gerais and to verify whether the T. gondii genotypes circulating in domestic animals correspond to the genotypes detected in humans. Genetic variability was assessed by restricted fragment length polymorphism at 11 loci (SAG1, 5′+3′SAG2, SAG2 alt, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). Twelve different genotypes were identified among the 24 isolates studied, including 8 previously identified genotypes and 4 new genotypes. The genetic relationship of the 24 T. gondii isolates, together with the genotypes previously described from 24 human newborns with congenital toxoplasmosis, revealed a high degree of similarity among the genotypes circulating in humans and animals in Minas Gerais. The most common genotypes among these species were BrII, BrIII, ToxoDB #108, and ToxoDB #206. Restricted fragment length polymorphism at the CS3 locus of these 48 isolates showed that the majority of isolates presented alleles I (50%) or II (27%). Isolates harboring allele III at the CS3 locus presented low virulence for mice, whereas those harboring alleles I or II presented higher virulence. These results confirm the utility of marker CS3 for predicting the virulence of Brazilian isolates of T. gondii in mice. No association was found between the allele type and clinical manifestations of human congenital toxoplasmosis. This is the first report of T. gondii genotyping that verifies the overlapping genotypes of T. gondii from humans and animals in the same geographic region of Brazil. Our results suggest that there is a common source of infection to the species studied, most likely oocysts contaminating the environment.

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Section: Introductionmentioning

confidence: 99%

Overlapping Toxoplasma gondii Genotypes Circulating in Domestic Animals and Humans in Southeastern Brazil

et al. 2014

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“…However, recent studies with multilocus markers indicate greater genetic diversity than initially thought among isolates of T. gondii worldwide [5, 6]. Toxoplasma gondii presents a complex population structure with a mix of clonal and sexual propagation [5].…”

Section: Introductionmentioning

confidence: 99%

Isolation and genotyping of viable Toxoplasma gondii from sheep and goats in Ethiopia destined for human consumption

Gebremedhin

Abdurahaman

Tessema

et al. 2014

Parasites & Vectors

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BackgroundToxoplasma gondii is an obligate intracellular protozoan parasite that infects humans and a broad spectrum of warm-blooded vertebrates. The present study was undertaken with the objectives of isolation and determining the genotypes of T. gondii strains from sheep and goats slaughtered in East and West Shewa Zones of Oromia Regional State, Central Ethiopia.MethodsHearts of 47 sheep and 44 goats that were seropositive in the Direct Agglutination Test (DAT) were bioassayed in mice. A multiplex PCR assay with 15 microsatellite markers was employed for genotyping of T. gondii isolates from sheep and goats.ResultsViable T. gondii were isolated from 47 (51.65%) animals, 27 sheep and 20 goats. Most isolates caused sub-clinical infections in mice, however, 2 sheep and 1 goat isolates were mouse-virulent, killing mice between 19–27 days post-inoculation. The success of T. gondii isolation in mice increased significantly (P = 0.0001) with higher DAT antibody titers in sheep and goats. Genotyping revealed that 29 (87.88%) of the 33 isolates were Type II, 3 (9.09%) were Type III and 1 (3.03%) was atypical. Three strains (one type II, one type III, and the atypical genotype) were virulent for mice.ConclusionsT. gondii tissue cysts in sheep and goats slaughtered for human consumption are widespread. This is the first report on isolation and genotyping of T. gondii from sheep and goats of Ethiopia.Electronic supplementary materialThe online version of this article (doi:10.1186/1756-3305-7-425) contains supplementary material, which is available to authorized users.

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“…gondii . The larger number of polymorphisms may be a characteristic of the Brazilian atypical isolates because they are genetically different and more diverse compared to those found in North America and Europe [8, 16]. Seven mutation points, leading to a change in the DHPS protein amino acids, were observed in the Brazilian strains isolated from infants with congenital toxoplasmosis.…”

Section: Discussionmentioning

confidence: 99%

“…gondii tachyzoites from each isolate were obtained from the peritoneal cavities of Swiss mice as previously described [16]. Fresh tachyzoites were submitted for DNA extraction using the kit Wizard® Genomic DNA Purification (Promega), according to the manufacturer’s instructions.…”

Section: Methodsmentioning

confidence: 99%

Genetic Polymorphisms and Phenotypic Profiles of Sulfadiazine-Resistant and Sensitive Toxoplasma gondii Isolates Obtained from Newborns with Congenital Toxoplasmosis in Minas Gerais, Brazil

et al. 2017

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BackgroundPrevious Toxoplasma gondii studies revealed that mutations in the dhps (dihydropteroate synthase) gene are associated with resistance to sulfonamides. Although Brazilian strains are genotypically different, very limited data are available regarding the susceptibility of strains obtained from human to sulfonamides. The aim of this study was to evaluate the efficacy of sulfadiazine (SDZ) against Brazilian isolates of T. gondii and verify whether isolates present polymorphisms in the dhps gene. We also investigated whether the virulence-phenotype and/or genotype were associated with the profile of susceptibility to SDZ.MethodsFive T. gondii isolates obtained from newborns with congenital toxoplasmosis were used to verify susceptibility. Mice were infected with 104 tachyzoites and orally treated with different doses of SDZ. The mortality curve was evaluated by the Log-rank test. The presence of polymorphisms in the dhps gene was verified using sequencing. A descriptive analysis for 11 Brazilian isolates was used to assess the association between susceptibility, genotype, and virulence-phenotype.ResultsStatistical analysis showed that TgCTBr03, 07, 08, and 16 isolates were susceptible to SDZ, whereas TgCTBr11 isolate presented a profile of resistance to SDZ. Nineteen polymorphisms were identified in dhps exons. Seven polymorphisms corresponded to non-synonymous mutations, with four being new mutations, described for the first time in this study. No association was found between the profile of susceptibility and the virulence-phenotype or genotype of the parasite.ConclusionsThere is a high variability in the susceptibilities of Brazilian T. gondii strains to SDZ, with evidence of drug resistance. Despite the large number of polymorphisms identified, the profile of susceptibility to SDZ was not associated with any of the dhps variants identified in this study. Other genetic factors, not yet determined, may be associated with the resistance to SDZ; thus, further studies are needed as a basis for a more adequate toxoplasmosis treatment.

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Genetic analysis of natural recombinant Brazilian Toxoplasma gondii strains by multilocus PCR–RFLP

Cited by 110 publications

References 46 publications

Overlapping Toxoplasma gondii Genotypes Circulating in Domestic Animals and Humans in Southeastern Brazil

Overlapping Toxoplasma gondii Genotypes Circulating in Domestic Animals and Humans in Southeastern Brazil

Isolation and genotyping of viable Toxoplasma gondii from sheep and goats in Ethiopia destined for human consumption

Genetic Polymorphisms and Phenotypic Profiles of Sulfadiazine-Resistant and Sensitive Toxoplasma gondii Isolates Obtained from Newborns with Congenital Toxoplasmosis in Minas Gerais, Brazil

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