DOI: 10.2478/s11686-013-0128-8 © W. Stefan´ski Institute of Parasitology, PAS Acta Parasitologica, 2013, 58(2), 185–190; ISSN 1230-2821 Differential detection of Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii in fecal samples by nested PCR in the United Arab Emirates (UAE) Ali ElBakri 1 , Amidou Samie 2 , Sinda Ezzedine 1 and Raed Abu Odeh 1 * 1 Department of Medical Laboratory Technology, College of Health Sciences, University of Sharjah, Sharjah, UAE; 2 Department of Microbiology, University of Venda, Thohoyandou, South Africa Abstract Amoebiasis is one of the most important infectious diseases afflicting mainly tropical and subtropical countries. This study was carried out in the Sharjah Emirate, UAE in order to accurately detect and differentiate Entamoeba histolytica, Entamoeba dispar and E. moshkovskii in fecal samples collected from the Sharjah municipality public health clinic by ELISA and nested polymerase chain reaction (PCR). One hundred and twenty specimens were examined and the PCR was positive for E. his- tolytica, E. dispar and E. moshkovskii (collectively referred to as Entamoeba complex) in 19.2% (23 out of 120). Of those, 10% (12/120) were mono - infection with E. histolytica; 2.5% (3/120) with E. dispar; and 2.5% (3/120) E. moshkovskii. The nested PCR also detected mixed infections by both E. histolytica and E. dispar in 3.3% (4/120) and E. dispar and E. moshkovskii in 0.8% (1/120). The TechLab ELISA kit failed to detect E. histolytica in any of the E. histolytica PCR positive samples. Over- all, the percentage of E. histolytica including those found in mixed infections was 13.3% (16/120). Compared to nested PCR, microscopy was found to have an overall sensitivity of 52.2% and a specificity of 75.2% for detection of Entamoeba complex. The present study indicates that E. histolytica is present in the UAE with an average incidence rate of 13.3%. However, larger studies need to be conducted in order to confirm these findings. We propose the use of PCR in both the routine diagnosis of amoebiasis and epidemiological survey in the UAE. Keywords Diarrhea, Entamoeba, epidemiology, Sharjah Introduction Entamoeba histolytica is a gut dwelling protozoan parasite that causes intestinal amoebiasis and amoebic liver abscess (ALA) worldwide (Walsh 1986). The disease amoebiasis still remains a major cause of morbidity and mortality in the de- veloping world (Mortimer and Chadee 2010; Ravdin 1995). It is well established that about 500 million individuals are in- fected globally each year, resulting in up to 100,000 deaths annually (W.H.O. 1997). With the occurrence of two other non-pathogenic species of Entamoeba namely E. dispar (W.H.O. 1997) and E. moshkovskii (Ali et al. 2003), the path- ogenic E. histolytica is often inaccurately reported or diag- nosed. Still the only tool used for the detection of E. histolytica in most countries, light microscopy, cannot distinguish be- tween the morphologically identical yet genetically distinct three species of Entamoeba. Consequently, it is now believed that epidemiological figures on the disease and its spread are overemphasized since they relied on microscopic identifica- tion only (Ali et al. 2008). There is, therefore, a need to iden- tify E. histolytica accurately using more specific and sensitive tools. Various types of serological assays such as gel diffusion precipitation test and enzyme-linked immunosorbent assay (ELISA) have been used to distinguish between E. histolytica and E. dispar. They were nevertheless, found to be inadequate in highly endemic regions and new detection methodologies such as antigen detection ELISA and polymerase chain reac- tion (PCR) have since been developed (Haque et al. 2003; Othman et al. 2010; Ackers 2002; Tanyuksel and Petri 2003). Both techniques are widely used nowadays for detecting and identifying E. histolytica in clinical samples. However, a no- table disadvantage of stool antigen immunoassay kits is their inability to detect neither E. dispar nor E. moshkovskii in clin- *Corresponding Author: abuodeh@sharjah.ac.ae Unauthenticated Download Date | 7/27/18 4:59 AM