Molecular study for the virulence factors Gal/GalNAc lectin and Amoebapores genes isolated from patients infected with Entamoeba histolytca in Thi Qar province/Iraq

The parasite Entamoeba histolytica is a major public health concern and globally important. Due to the widespread of the E. histolytica infection in Thi Qar province, the aim of this study, was to detect E. histolytica by using polymerase chain reaction (PCR), and to study the pathogenicity of E. histolytica in human through detecting the virulence factor Gal/GalNAc lectin and Amoebapores genes and comparing the local isolates of this genes with globally genetic sequencing of National Center for Biotechnology Information NCBI. The diagnosis of E. histolytica parasites in human stool based on the diagnostic 18s rRNA gene. About 572 stool samples were collected from patients, who suffer from diarrhea and complain of abdominal pain in the Al-Hussein Teaching Hospital, Bint Al-Huda Educational Hospital for Women and Children and Mohammed Al-Musawi Hospital in Thi-Qar Province during the period from the beginning of December 2023 to the end of May 2024. The results of current study showed 100 out of 572 stool samples were infected with E. histolytica parasites according to microscopic examination with prevalence 17.48%. The molecular diagnosis recorded 64 out of 100 samples were positive to diagnostic 18s rRNA gene with  prevalence 64%. The virulence factor Gal/GalNAc lectin was positive in 50 samples out of 50 examined samples with prevalence 100%  by using PCR technology. The results also showed the presence of the gene for the virulence factor Amebopore in 34 out of 50 samples infected with the E. histolytica parasite, at a rate of 68%.  The genetic sequence of Gal/GalNAc lectin and Amoebapores genes were performed and compared with the genetic sequence of virulence factors registered globally at the NCBI. The results of the study recorded that the virulence factor gene Gal/GalNAc has the highest degree of genetic homology (98.68% - 99.14%) and the lowest genetic variability (0.0020% - 0.0180%). The results of the current study also showed that the multiple genetic sequences of this gene for three local isolates of the E.histolytica parasite showed a high genetic correlation between the three local isolates and the global strain from the United States of America with the serial number USA (M59850.1). The local isolate with the serial number (PQ049161) was the most identical with a percentage of 99.14% and the least heterogeneous with a percentage of 0.16%. The results of the current study of the virulence factor gene Amoebapore C showed high genetic similarity (99.71%-99.42%) with low genetic variability (1.67%-1.90%). The results of multiple gene sequencing analysis of three local isolates of E. histolytica parasite also showed a high genetic linkage between the three local isolates and the global strain from India with the serial number ALA1 (KP159522.1). The local isolate with the serial number PQ049148 was the most identical with a percentage of 99.71% and the lowest percentage of variability 0.29%. .These findings suggest a high degree of genetic similarity between the local Iraqi E. histolytica isolates and the reference strain, potentially indicating similar virulence profiles.