Ricerc@Sapienza

Among the intestinal pathogenic Escherichia coli, enteroinvasive E. coli (EIEC) are a group of intracellular pathogens able to enter epithelial cells of colon, multiplicate within them, and move between adjacent cells with a mechanism similar to Shigella, the ethiological agent of bacillary dysentery. Despite EIEC belong to the same pathotype of Shigella, they neither have the full set of traits that define Shigella nor have undergone the extensive gene decay observed in Shigella. Molecular analysis confirms that EIEC are widely distributed among E.

Shigella, the etiological agent of bacillary dysentery (shigellosis), is a highly adapted human pathogen. Itevolved from an innocuous ancestor resembling the Escherichia coli strain by gain and loss of genes andfunctions. While the gain process concerns the acquisition of the genetic determinants of virulence, theloss is related to the adaptation of the genome to the new pathogenic status and occurs by pathoadaptivemutation of antivirulence genes. In this study, we highlight that the SRRz/Rz1lambdoid lysis cassette, eventhough stably adopted in E.