Differentiation of Entamoeba histolytica and Entamoeba disparcomplex by multiplex polymerase chain reaction

Abstract

Entamoeba histolytica is the causative agent of human amoebiasis. It is one of the most common parasitic infections worldwide, third only to malaria and schistosomiasis. Amoebiasis infects approximately 50 million people causing 40,000 to100,000 deaths per annum. In Africa, infection varies in different countries depending on their social economic factors. Clinical manifestation of amoebiasis is due to existence of two morphologically identical species but have different biochemical and genetic makeup. Entamoeba dispar is a commensal species, while Entamoeba histolytica is a pathogenic one, but both of them can occur together during incidences of infection. Thus, it is of clinical importance to differentiate between the two species, for correct treatment decision, management and public health. Infection occurs mainly by ingestion of viable cysts from contaminated sources such as water and food. The main objective of this study was to differentiate Entamoeba histolytica and Entamoeba dispar by multiplex polymerase reaction in stool samples. A descriptive survey research was adopted between January 2012 and April 2012 and one hundred and sixty nine (169) freshly collected stool samples from patients seeking medical services at outpatient department in Naivasha District hospital with symptoms of amoebiasis were analyzed using microscopy and multiplex polymerase chain reaction techniques. Data for the presence of the two species of Entamoeba were analysed using multivariate statistics and Chi-square (χ2). Microscopy detected 36 (21.3%) patients were infected with E. histolytica /Entamoeba dispar complex cysts or trophozoites. On the other hand, multiplex polymerase chain reaction identified 42 (24.9%) patients who had DNA of E. histolytica or Entamoeba dispar in their stool samples. Mono infection with Entamoeba dispar was the highest with 34 (20.1%), followed by Entamoeba histolytica 4 (2.4%) and co-infection with both species at 4 (2.4%). Generally multiplex polymerase chain reaction technique reduced the chances of misdiagnosis by 9 (6.7%) patients. The study showed that multiplex polymerase chain reaction is a useful diagnostic tool for distinction between Entamoeba histolytica and Entamoeba dispar complex as well as the presence of mixed infection simultaneously in a single polymerase chain reaction steps in laboratory analyses. Despite the cost of carrying out the technique being higher compared to conventional microscopy, multiplex polymerase chain reaction is more sensitive and specific in detection and differentiation of Entamoeba histolytica and Entamoeba dispar. To the best of my knowledge this is the first report to differentiate Entamoeba histolytica and Entamoeba dispar from human faecal samples from Kenya and its implications are further discussed.