Applied Microbiology: Open Access
Open Access

Abstract

Genetic Diversity in Escherichia coli

Benyam Zenebe*, Tesfaye Sisay and Gurja Belay

E. coli are genetically diverse bacteria which can live in different habitats. The E. coli genome has two components: The core genome which contains essential genes and is shared among all strains of the species; and the accessory genome which is highly variable among strains encompassing many mobile genetic elements. Despite the extensive dynamics in the genomic content over evolutionary period, the genome size of E. coli seems to have been conserved due to processes of continuous gene gain and gene loss. Mobile genetic elements give strains of E. coli better adaptability to different environments such as the ability to resist antibiotics and to escape immune responses and establish infection in various hosts. Mobile genetic elements have been detected in both commensal and pathogenic strains. Horizontal gene transfer in the form of transformation, transduction, and conjugation plays a big role in the genetic diversification, evolution, and adaptation of various E. coli strains besides genome mutation events which vary in rates among wild type and domestic strains with domestic strains displaying increased mutability due to reduced methyl directed mismatch repair activity.

E. coli genetic diversity has been studied from the stand point of traits such as: Antibiotic resistance, repeat sequences, insertion sequences, bacteriophage susceptibility, DNA hybridization characteristics, plasmids, restriction fragment polymorphisms and different molecular techniques have been devised to study the genetic diversity of E. coli strains based on such traits. E. coli bacteria are highly genetically diverse as indicated by the recovery of genetically diverse strains from different habitats by different researchers. Some multi drug resistant strains have attained a worldwide distribution. Host, environment or season related genetic diversity or relatedness is observed among phylogeny groups and strains of E. coli although different studies on the host/environment based genetic structure of E. coli do not come up with similar results.

Published Date: 2024-06-21; Received Date: 2023-07-29