To determine the presence of Entamoeba histolytica/E. dispar and E. moshkovskii in stool samples, tRNA-based short tandem repeat gene polymorphism in E. histolytica isolates, and the relationship between amoeba load and clinical outcome in studies. Materials and methods: This study involved 840 stools samples of individuals having diarrhea/dysentery and individuals who were asymptomatic by using microscopy, culture, E. histolytica antigen ELISA, and conventional/real-time PCR methods. Results: Of the 840 samples analyzed, 4.3% (36/840), 2.6% (22/840), and 7.4% (62/840) of the stool samples were determined to be positive by E. histolytica antigen ELISA, and real-time PCR for E. histolytica and E. dispar, respectively. Thirty-five of the 62 (56.4%) samples positive for E. dispar and 20 of the 22 (91.0%) samples positive for E. histolytica were from dysenteric individuals as revealed by real-time PCR. Although there was no statistically significant difference in patients with diarrhea, a correlation might be seen between amoeba load and clinical outcome in those infected with E. histolytica, since amoeba load was usually determined 103 copies/mL or higher in patients with diarrhea. In this study, 3 different genotypes were defined in 16 isolates by using 6 loci (A-L, N-K2, D-A, R-R, S-D, and STGA-Q). Conclusion: Our results demonstrated that real-time PCR is a useful, reliable, and sensitive method for the determination of E. histolytica in stools and for differentiation from E. dispar. It is suggested that parasite load might affect clinical outcome.

To determine the presence of Entamoeba histolytica/E. dispar and E. moshkovskii in stool samples, tRNA-based short tandem repeat gene polymorphism in E. histolytica isolates, and the relationship between amoeba load and clinical outcome in studies. Materials and methods: This study involved 840 stools samples of individuals having diarrhea/dysentery and individuals who were asymptomatic by using microscopy, culture, E. histolytica antigen ELISA, and conventional/real-time PCR methods. Results: Of the 840 samples analyzed, 4.3% (36/840), 2.6% (22/840), and 7.4% (62/840) of the stool samples were determined to be positive by E. histolytica antigen ELISA, and real-time PCR for E. histolytica and E. dispar, respectively. Thirty-five of the 62 (56.4%) samples positive for E. dispar and 20 of the 22 (91.0%) samples positive for E. histolytica were from dysenteric individuals as revealed by real-time PCR. Although there was no statistically significant difference in patients with diarrhea, a correlation might be seen between amoeba load and clinical outcome in those infected with E. histolytica, since amoeba load was usually determined 103 copies/mL or higher in patients with diarrhea. In this study, 3 different genotypes were defined in 16 isolates by using 6 loci (A-L, N-K2, D-A, R-R, S-D, and STGA-Q). Conclusion: Our results demonstrated that real-time PCR is a useful, reliable, and sensitive method for the determination of E. histolytica in stools and for differentiation from E. dispar. It is suggested that parasite load might affect clinical outcome.