Identification and genetic characterization of a new Brazilian genotype of Toxoplasma gondii from sheep intended for human consumption

Abstract Recent studies have demonstrated that strains of Toxoplasma gondii in Brazil are frequently different from those detected in other countries, thus making an accurate phylogenetic analysis difficult. The aim of this study was to genetically characterize T . gondii samples from sheep raised in southern Bahia and intended for human consumption, by means of PCR–RFLP and sequencing techniques. Experimental samples were obtained from 200 sheep brains purchased at butcher's shops in Itabuna, Bahia, Brazil. In total, three samples (#54, #124 and #127) were T . gondii -positive. The application of multilocus PCR–RFLP using ten molecular markers (SAG1, SAG2, SAG3, BTUB, c22-8, PK1, GRA6, L358, c-29-2 and Apico) revealed a single genotype common to all samples of this study, which differed from any other published T . gondii genotypes. An atypical allele was detected in the L358 genetic marker; this has not previously been shown in any other South American T . gondii isolates. Phylogenetic analysis on the sequences from multilocus PCR sequencing revealed that these three samples were classified into the same lineage. Extensive indel regions were detected in the Apico genetic marker. Together, our findings revealed a new Brazilian T . gondii genotype. Further research should be conducted to enrich the database of Brazilian T . gondii genotypes from different regions. This will make it possible to understand the phylogenetic relationship between isolates.