Genotypic characterization of Toxoplasma gondii strains associated with human toxoplasmosis in Spain: Direct analysis from clinical samples

Genetic analysis of the SAG2 locus was performed to determine the prevalenc e of the different genotypes of Toxoplasma gondii (strain types I, II, and III) associated with human toxoplasmosis in Spain. This determination was m ade directly from primary clinical samples, obviating the previous process of isolation in mice or cell culture. A total of 34 isolates of T, gondii, collected from immunocompromised patients and congenital infection cases, w ere analyzed. Restriction fragment length polymorphism in PCR-amplified SAG 2 products was used to group strains into one of the three genotypes of T, gondii, Complete characterization of the SAG2 gene was successful in 76.5% of the cases, demonstrating the feasibility of direct genotype analysis fro m clinical samples of different origins. Strains of T, gondii type II were the most prevalent in immunocompromised patients, with 52% of cases, while strains of type I were present in 75% of the congenital infection cases. Th ese data differ from previous reports that show type II strains to be mostl y associated with all kinds of human toxoplasmosis. These differences might be an effect of selection in the process of culture and isolation of the s amples performed by other researchers prior to strain characterization.