Molecular Detection of Shigella spp. and Entamoeba histolytica Causing Bacillary and Amoebic Dysentery Among Children in Ramadi City


Background and objective:- Dysentery as any episode of diarrhea in which there is blood in loose and watery stool, there are different types of pathogens that can cause acute dysentery, including Shigella spp. and Entamoeba histolytica. The aims of this study was to isolate Shigella spp. and Entamoeba histolytica causing both bacillary and amoebic dysentery respectively, in children less than five years of age by conventional techniques. Also, molecular detection of Shigella spp. and Entamoeba histolytica was achieved. Patients and methods:- One hundred and forty five stool specimens obtained from children were admitted Maternity and Child Teaching Hospital in Ramadi with acute diarrhea with the mean age (2.168±12.571) were enrolled in the study from January 2014 to March 2015. PCR was used to amplify specific oligonucleotide sequences with 320 base pair coding for (ial) gene for Shigella spp. and Entamoeba histolytica (16S-rRNA) gene with 439 base pair.Results:- The stool specimens had been taken from 145 patients divided into 75(51.7%) patients yielded amoebic dysentery and others 70(48.3%) from these with bacillary dysentery. In the molecular part of this study molecular part of study, our results showed that 30 out of 75(40%) extracted DNA for E. histolytica were produced strong bands revealed positivity of PCR technique while the other 45(60%) were negative. The result of PCR technique among Shigella spp. revealed that 30 out of 70(42.86%) were positive and in contrast 40/70 (57.14%) samples were negative.Conclusion:- The study suggested that PCR has several advantages over the conventional methods for the diagnosis of bacillary and amoebic dysentery such as safety, high sensitivity and specificity. Our results demonstrated that the value of using a combination of traditional and molecular techniques in the diagnosis of diarrheal disease in this population. This study has been providing comparable results of microscopy and PCR, none of these methods can detect all positives alone. According to our findings, microscopy is a simple analysis, but it is subjective, needs experience to evaluate and should be combined with complimentary methods such as antigen detection and PCR for identification of the species to avoid false and/ or insufficient diagnosis and treatment applications.