Comparison of IncL/M Plasmids Using the Neighbor-Joining Method on Basis repA and excA Genes

The aim of this study is to make comparison of IncL/M groups on basis of two genes candidates’ repA and excA genes. The sequences of 27 plasmids were compared using the neighbor-joining method. This method was used to construct a phylogenetic tree for the nucleotide sequences of two genes (repA and excA), using the program MEGA X software. The evolutionary distances were computed using the maximum composite likelihood method. The neighbor-joining method analysis showed different results based on the gene used for comparison. The repA gene was more accurate than excA gene to distinguish between different incL/M plasmids. This study suggested that IncL/M plasmids harboring different antibiotic resistance genes have evolved differently.