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Genetic analysis of a region of 16s-like ribosomal RNA gene of <i>Entamoeba species</i> from diarrhoeic stool samples in Kaduna State, Nigeria


I.S. Dawah
H.I. Inabo
I.O. Abdullahi
A.D. Machido
D.D. Garba

Abstract

Background: Genetic mutations and other polymorphisms in genes, gene systems, or whole genomes are vital in the pathogenesis and  epidemiology of Amoebiasis.
Aim: The study aimed at investigating intra-species genetic variation in E. histolytica, Entamoeba dispar and Entamoeba moshkovskii from stool samples of diarrhoeic patients in Kaduna State, Nigeria.
Methods: The DNA extracted from microscopic positive stool samples was used in the amplification of a part of the genus Entamoeba  small-subunit ribosomal RNA gene (SSU rDNA) with Nested Multiplex Polymerase Chain Reaction (NM-PCR) and followed by DNA  sequencing.
Results: This study revealed that out of the 16 PCR positive samples, 3 (18.8%) contained only Entamoeba histolytica, 7 (43.8%) contained  only Entamoeba dispar and 2 (12.5%) contained only Entamoeba moshkovskii. Mixed infection with Entamoeba dispar and Entamoeba  histolytica was found in 3 (18.8%) samples, while only 1 (6.3%) sample had Entamoeba dispar and Entamoeba moshkovskii. The study also  revealed considerable number of nucleotide polymorphisms in the form of deletion, substitution and punctual insertion mutation at  different positions of the 16S-like ribosomal nucleotide sequences of the three Entamoeba species. A total of 14 genotypes of  Entamoeba species, comprising six E. histolytica genotypes, six E. dispar genotypes and two E. moshkovskii genotypes were identified. The  phylogenetic analysis within the sequences of Entamoeba species isolates suggested three different variants present among the  diarrhoeic patients. Conclusion: The existence of high level of diversity reported in this study suggests that a rapid generation of new  Entamoeba variants is occurring in Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii infecting humans. Further studies  in the complete ribosomal RNA gene of these species would possibly reveal more genetic information on Entamoeba.