Detection of Entamoeba Spp. in Jordanian Clinical Samples by Traditional and Molecular Methods

Objective: To evaluate the efficacy of polymerase chain reaction (PCR), enzyme-linked immune-sorbent assay (ELISA), and immunochromatography-based methods compared to conventional microscopy for detecting Entamoeba histolytica in diarrheal stool samples, and to identify a reliable diagnostic tool for amoebiasis. Methods: A total of 68 fresh diarrheal stool samples were collected from three hospitals in Amman. Samples were tested using microscopy, TechLab E. histolytica II ELISA, and nested-PCR. Additionally, Operon Simple immunochromatography test was performed on 29 randomly selected samples. Detection rates of the methods were compared, and the concordance between techniques was analyzed. Results: Microscopy detected E. histolytica cysts and/or trophozoites in 76.5% (52/68) of the samples, while ELISA and PCR detected the parasite in 10.3% (7/68) and 29.4% (20/68), respectively. Among the 29 samples tested by immunochromatography, 79.3% (23/29) were positive by microscopy, and 48.3% (14/29) were positive for E. histolytica antigen. Discrepancies were noted, as 3 PCR-positive samples were negative by both ELISA and microscopy, and 7 of the microscopically negative samples were PCR-positive. Immunochromatography detected antigens in 2 of the 16 microscopically negative samples. Conclusion: None of the methods was found superior to microscopy, though microscopy's limitations, such as its inability to distinguish pathogenic from non-pathogenic Entamoeba species, compromise its reliability. Antigen- and DNA-based methods demonstrated higher specificity, with immunochromatography outperforming ELISA and PCR in simplicity and usability. Further studies with larger sample sizes and a standardized reference method are needed to establish the most effective diagnostic approach for E. histolytica.