Escherichia coli and Virulence Genes: Unraveling the Genetic Basis of Pathogenicity
Escherichia coli (E. coli) is a highly versatile bacterial species that can exist both as a harmless commensal in the human intestinal microbiota and as a pathogenic organism capable of causing a wide spectrum of diseases. The pathogenic potential of E. coli is largely determined by the acquisition and expression of virulence genes, many of which are located on mobile genetic elements such as plasmids, bacteriophages, and pathogenicity islands. These genes encode a variety of factors, including adhesins that promote host cell colonization, toxins that disrupt cellular processes, iron acquisition systems that support bacterial survival in nutrient-limited environments, and secretion systems that deliver effector proteins into host cells. Different E. coli pathotypes, such as enteropathogenic (EPEC), enterohemorrhagic (EHEC), uropathogenic (UPEC), and enterotoxigenic (ETEC) strains, possess distinct sets of virulence genes that define their disease manifestations, ranging from diarrhea to urinary tract infections and systemic complications. Understanding the genetic basis of E. coli virulence is essential for developing targeted diagnostic tools, novel therapeutics, and effective preventive strategies against infections.
