Original Article

Genotyping of Toxoplasma gondii Strains Isolated from Patients with Ocular Toxoplasmosis in Iran


Background: Toxoplasma gondii is an obligate, intracellular protozoon that develops its sexual stage in cat’s intestinal epithelial cells as definitive host and develops its asexual stage in different tissues of a wide range hosts called intermediate host. The protozoon is a food-borne and worldwide parasite that can cause serious complications such as abortion in pregnant women, encephalitis, and ocular toxoplasmosis. The present study aimed to genotype T. gondii strains isolated from patients with toxoplasmic retinochoroiditis.

Methods: Fifty-two blood samples were taken from patients with ocular toxoplasmosis, from July 2013 to July 2014. The specimens were collected from three ophthalmological hospitals of Tehran, Iran. After that, DNA extraction was performed using kit on separated buffy coats of serologically positive blood samples. Then PCR was done in GRA6 gene. For digestion of products, MseI endonuclease was used. Finally, some of the PCR products were sequenced.

Results: All of 52 samples were found positive by serological and PCR-RFLP methods and all of isolated strains belong to type III genotype. Type III genotype has the highest prevalence in Iranian ocular toxoplasmic patients.

Conclusion: T. gondii, particularly its type III should not be neglected as a cause of retinochoroiditis.

Dubey JP. Toxoplasmosis of animals and humans: CRC press; 2009.

Nardoni S, Angelici MC, Mugnaini L, Mancianti F. Prevalence of Toxoplasma gondii infection in Myocastor coypus in a protected Italian wetland. Parasit Vectors. 2011;4:240.

Zhou P, Chen Z, Li H-L, Zheng H, He S, Lin R-Q, et al. Toxoplasma gondii infection in humans in China. Parasit Vectors. 2011;4(1):165.

Chen J, Xu M-J, Zhou D-H, Song H-Q, Wang C-R, Zhu X-Q. Canine and feline parasitic zoonoses in China. Parasit Vectors. 2012;5:152.

Tian Y-M, Dai F-Y, Huang S-Y, Deng Z-H, Duan G, Zhou D-H, et al. First report of Toxoplasma gondii seroprevalence in peafowls in Yunnan Province, Southwestern China. Parasit Vectors. 2012;5:205.

Mead PS, Slutsker L, Dietz V, McCaig LF, Bresee JS, Shapiro C, et al. Food-related illness and death in the United States. Emerg Infect Dis. 1999;5(5):607.

Assmar M, Amirkhani A, Piazak N, Hovanesian A, Kooloobandi A, Etessami R. [Toxoplasmosis in Iran. Results of a seroepidemiological study]. Bull Soc Pathol Exot. 1997; 90(1):19-21.

Wong S-Y, Remington JS. Toxoplasmosis in pregnancy. Clin Infec Dis. 1994:853-61.

Israelski D, Remington J. Toxoplasmosis in the non-AIDS immunocompromised host. Curr Clin Top Infect Dis. 1993;13:322-56.

Cristina N, Dardé ML, Boudin C, Tavernier G, Pestre-Alexandre M, Ambroise-Thomas P. A DNA fingerprinting method for individual characterization of Toxoplasma gondii strains: combination with isoenzymatic characters for determination of linkage groups. Parasitol Res. 1995;81(1):32-7.

Dardé M, Bouteille B, Pestre-Alexandre M. Isoenzyme analysis of 35 Toxoplasma gondii isolates and the biological and epidemiological implications. J Parasitol. 1992:786-94.

Guo Z, Johnson A. Genetic characterization of Toxoplasma gondii strains by random amplified polymorphic DNA polymerase chain reaction. Parasitology. 1995;111(Pt 2):127-32.

Howe DK, Honoré S, Derouin F, Sibley LD. Determination of genotypes of Toxoplasma gondii strains isolated from patients with toxoplasmosis. J Clin Microbiol. 1997; 35(6):1411-4.

Pena H, Gennari S, Dubey J, Su C. Population structure and mouse-virulence of Toxoplasma gondii in Brazil. Int J Parasitol. 2008;38(5):561-9.

Sibley LD, Boothroyd JC. Virulent strains of Toxoplasma gondii comprise a single clonal lineage. Nature. 1992;359(6390):82-5.

Ajzenberg D, Banuls A, Su C, Dumetre A, Demar M, Carme B, et al. Genetic diversity, clonality and sexuality in Toxoplasma gondii. Int J Parasitol. 2004;34(10):1185-96.

Howe DK, Sibley LD. Toxoplasma gondii comprises three clonal lineages: correlation of parasite genotype with human disease. J Infec Dis. 1995:1561-6.

Mercier C, Adjogble KD, Däubener W. Dense granules: are they key organelles to help understand the parasitophorous vacuole of all apicomplexa parasites? Int J Parasitol. 2005;35(8):829-49.

Michelin A, Bittame A, Bordat Y, Travier L, Mercier C, Dubremetz J-F, et al. GRA12, a Toxoplasma dense granule protein associated with the intravacuolar membranous nanotubular network. Int J Parasitol. 2009;39(3):299-306.

Cesbron-Delauw M, Guy B, Torpier G, Pierce R, Lenzen G, Cesbron J, et al. Molecular characterization of a 23-kilodalton major antigen secreted by Toxoplasma gondii. Proc Natl Acad Sci. 1989;86(19):7537-41.

Charif H, Darcy F, Torpier G, Cesbron-Delauw M-F, Capron A. Toxoplasma gondii: characterization and localization of antigens secreted from tachyzoites. Exp Parasitol. 1990;71(1):114-24.

Leriche MA, Dubremetz JF. Exocytosis of Toxoplasma gondii dense granules into the parasitophorous vacuole after host cell invasion. Parasitol Res. 1990;76(7):559-62.

Achbarou A, Mercereau-Puijalon O, Sadak A, Fortier B, Leriche M, Camus D, et al. Differential targeting of dense granule proteins in the parasitophorous vacuole of Toxoplasma gondii. Parasitology. 1991;103(Pt 3):321-9.

Mercier C, Lecordier L, Darcy F, Deslee D, Murray A, Tourvieille B, et al. Molecular characterization of a dense granule antigen (Gra 2) associated with the network of the parasitophorous vacuole in Toxoplasma gondii. Mol Biochem Parasitol. 1993;58(1):71-82.

Mevelec M-N, Chardès T, Mercereau-Puijalon O, Bourguin I, Achbarou A, Dubremetz J-F, et al. Molecular cloning of GRA4, a Toxoplasma gondii dense granule protein, recognized by mucosal IgA antibodies. Mol Biochem Parasitol. 1992;56(2):227-38.

Dubremetz JF, Achbarou A, Bermudes D, Joiner KA. Kinetics and pattern of organelle exocytosis during Toxoplasma gondii/host-cell interaction. Parasitol Res. 1993;79(5):402-8.

Lecordier L, Mercier C, Torpier G, Tourvieille B, Darcy F, Li LJ, et al. Molecular structure of a Toxoplasma gondii dense granule antigen (GRA 5) associated with the parasitophorous vacuole membrane. Mol Biochem Parasitol. 1993;59(1):143-53.

Lecordier L, Moleon-Borodowsky I, Dubremetz J-F, Tourvieille B, Mercier C, Deslée D, et al. Characterization of a dense granule antigen of Toxoplasma gondii (GRA6) associated to the network of the parasitophorous vacuole. Mol Biochem Parasitol. 1995;70(1):85-94.

Arab-Mazar Z, Fallahi S, Koochaki A, Haghighi A, Tabaei SJS. Immunodiagnosis and molecular validation of Toxoplasma gondii-recombinant dense granular (GRA) 7 protein for the detection of toxoplasmosis in patients with cancer. Microbiol Res. 2016;183:53-9.

Rinder H, Thomschke A, Dardé ML, Löscher T. Specific DNA polymorphisms discriminate between virulence and non-virulence to mice in nine Toxoplasma gondii strains. Mol Biochem Parasitol. 1995;69(1):123-6.

Meisel R, Stachelhaus S, Mévélec M-N, Reichmann G, Dubremetz JF, Fischer H-G. Iddentification of two alleles in the GRA4 locus of Toxoplasma gondii determining a differential epitope which allows discrimination of type I versus type II and III strains. Mol Biochem Parasitol. 1996;81(2):259-63.

Costa JM, Dardé M-L, Assouline B, Vidaud M, Bretagne S. Microsatellite in the beta-tubulin gene of Toxoplasma gondii as a new genetic marker for use in direct screening of amniotic fluids. J Clin Microbiol. 1997;35(10):2542-5.

Arab-Mazar Z, Seyyed-Tabaei SJ, Mirahmadi H. Cloning of Dense Granular (GRA) 7 Gene of Toxoplasma gondii into pTZ57RT Vectors for Sub-Cloning in Prokaryotic and Eukaryotic Plasmids. Novel Biomed. 2014;2(4):114-9.

Fazaeli A, Carter P, Darde M, Pennington T. Molecular typing of Toxoplasma gondii strains by GRA6 gene sequence analysis. Int J Parasitol. 2000;30(5):637-42.

Honoré S, Couvelard A, Garin Y, Bedel C, Hénin D, Dardé M, et al. Génotypage de souches de Toxoplasma gondii chez des patients immunodéprimés. Pathol Biol. 2000;48(6):541-7.

Grigg ME, Ganatra J, Boothroyd JC, Margolis TP. Unusual abundance of atypical strains associated with human ocular toxoplasmosis. J Infect Dis. 2001;184(5):633-9.

Bossi P, Caumes E, Paris L, Dardé M-L, Bricaire F. Toxoplasma gondii-associated Guillain-Barré syndrome in an immunocompetent patient. J Clin Microbiol. 1998;36(12):3724-5.

Dardé ML, Villena I, Pinon JM, Beguinot I. Severe toxoplasmosis caused by a Toxoplasma gondii strain with a new isoenzyme type acquired in French Guyana. J Clin Microbiol. 1998;36(1):324-.

Parmley SF, Gross U, Sucharczuk A, Windeck T, Sgarlato GD, Remington JS. Two alleles of the gene encoding surface antigen P22 in 25 strains of Toxoplasma gondii. J Parasitol. 1994:293-301.

Glasner PD, Silveira C, Kruszon-Moran D, Martins MC, Burnier M, Silveira S, et al. An unusually high prevalence of ocular toxoplasmosis in southern Brazil. Am J Ophthalmol. 1992;114(2):136-44.

Boothroyd JC, Grigg ME. Population biology of Toxoplasma gondii and its relevance to human infection: do different strains cause different disease? Curr Opin Microbiol. 2002;5(4):438-42.

Switaj K, Master A, Borkowski PK, Skrzypczak M, Wojciechowicz J, Zaborowski P. Association of ocular toxoplasmosis with type I Toxoplasma gondii strains: direct genotyping from peripheral blood samples. J Clin Microbiol. 2006; 44(11):4262-4.

Vallochi AL, Muccioli C, Martins MC, Silveira C, Belfort R, Rizzo LV. The genotype of Toxoplasma gondii strains causing ocular toxoplasmosis in humans in Brazil. Am J Ophthalmol. 2005;139(2):350-1.

Ferreira IMR, Vidal JE, de Mattos CdCB, de Mattos LC, Qu D, Su C, et al. Toxoplasma gondii isolates: Multilocus RFLP–PCR genotyping from human patients in Sao Paulo State, Brazil identified distinct genotypes. Exp Parasitol. 2011;129(2):190-5.

Biradar SS, Saravanan BC, Tewari AK, Sreekumar C, Sankar M, Sudhakar NR. Genetic characterization of Toxoplasma gondii isolates from chickens in India by GRA6 gene sequence analysis. Acta Parasitol. 2014;59(4):666-74.

Rashidi S, Sadraei J, Moghadam MF, Pirestani M. Isolation and Molecular Characterization of Toxoplasma gondii Strains From Rats in Tehran. Jundishapur J Microbiol. 2012;5(4):537-41.

IssueVol 11 No 3 (2016) QRcode
SectionOriginal Article(s)
Genotyping Toxoplasma gondii Oclar toxoplasmosis GRA6 PCR-RFLP Iran

Rights and permissions
Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
How to Cite
NOROUZI M, SEYYED TABAEI SJ, NIYYATI M, SABER V, BEHNIAFAR H. Genotyping of Toxoplasma gondii Strains Isolated from Patients with Ocular Toxoplasmosis in Iran. Iran J Parasitol. 2016;11(3):316-324.