Molecular study for the virulence Factor EhCRT gene isolated from atients Infected with Entamoeba Histolytca in Thi Qar Province/Iraq

Abstract

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 EhCRT gene and comparing the local isolates of this gene 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 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 EhCRT was positive in 50 samples out of 50 examined samples with prevalence 100% by using PCR technology.  The genetic sequence of the EhCRT gene was performed and compared with the genetic sequence of virulence factors registered globally at the NCBI. All three local isolates (IQN.No.1-3) exhibited high sequence identity (98.68% - 98.91%) with the USA strain HM-1:IMSS (XM_650149.1), with genetic variations ranging from 1.09% to 1.22%. 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.