Tunisian Toxoplasma gondii strains genotyping by the use of AK69 marker

BACKGROUND: Clinical manifestation due to infection by Toxoplasma gondii is closely linked to the infecting strain of the parasite. Several genetic markers are available to determinate its genotype but few of them are able to discriminate between the three predominant lineages, namely types I, II and III. The number of markers decreases when atypical, recombinant/mixed genotypes need to be identified. FINDINGS: In our study, the contribution of sequence polymorphisms in the AK69 gene as typing markers for T. gondii was investigated for the first time in an epidemiological study. The coding region of the marker was amplified, sequenced and aligned for different Toxoplasma strains. The identified nucleotide polymorphism at 12 positions was able to highly discriminate between the different congenital toxoplasmosis Tunisian strains. Moreover the high detection sensitivity level of the marker enabled unambiguous identification of mixed/recombinant genotypes directly. CONCLUSION: It can be, thus, very useful for direct typing in areas where such genotypes are frequently encountered, mainly in the African continent.