Phylogenetic tree constructed of Salmonella enterica subspecies enterica isolated from animals and humans in Basrah and Baghdad governorates, Iraq

Abstract

The genetic relatedness of Salmonella enterica sub sp. enterica isolated from human and animal origin has more interest as its data possibly will offer an essential confirmation for the source of human infection. This study aimed to determine the genetic relationship of S. enterica subspecies enterica isolated from human and animal sources. A total of 300 samples were collected from two primary sources, human and animal, from two different regions, Baghdad and Basrah governorates. For constructing the phylogenetic Tree of Salmonella enterica subspecies enterica, the sequencing of PCR product (positive samples) for each target genes 16s rRNA, avrA, and spvC were analyzed using BLAST analysis to determine the similarities and differences between the Iraqi strains and the existing global strains. The similarity rate in the first gene 97.77%, the second gene 98.29%, and the third 96.82%, respectively. The genetic Tree of each of the three genes was set up separately using two methods, Maximum Likelihood, and the second Minimum evolution. The phylogenetic analysis reveals that Iraqi strains of Salmonella are highly similar, and they share the same sequence of 16s rRNA gene with national Salmonella strains. However, their bases of avrA and spvC genes are not similar. This difference leads us to conclude that the Iraqi Salmonella evolution path was characterized by its path in developing global strains with some correlation in some samples; it may be linked with the same ancestors from which it emerged.

Keywords

• salmonella enterica
• pcr
• phylogenetic tree