Shiga toxin gene (stx) (stx)

Shiga toxin genes (stx1 and stx2) are the primary virulence factors in Shiga toxin-producing Escherichia coli (STEC), including the O157:H7 serotype [CDC]. These genes are typically located on lambdoid prophages integrated into the bacterial chromosome and are expressed during the lytic cycle [StatPearls]. The encoded Shiga toxins are AB5-type toxins that consist of an enzymatically active A subunit and a pentameric B subunit responsible for cell binding [StatPearls]. Once inside a host cell, the A subunit acts as an N-glycosidase, cleaving a specific adenine residue from the 28S ribosomal RNA, which irreversibly halts protein synthesis and leads to apoptosis [StatPearls]. This cellular damage primarily affects the intestinal mucosa and the vascular endothelium, particularly in the kidneys, leading to hemorrhagic colitis and hemolytic uremic syndrome (HUS) [CDC]. While these DNA sequences are critical for the molecular diagnosis of STEC infections via PCR, they are not traditional therapeutic targets for small molecules or biologics [Nature Reviews Microbiology]. Instead, therapeutic development focuses on neutralizing the toxin protein or inhibiting its binding to host receptors like globotriaosylceramide (Gb3) [Nature Reviews Microbiology]. A significant clinical challenge is that certain antibiotics can induce the bacterial SOS response, which triggers prophage induction and significantly increases stx gene expression and toxin release [Frontiers in Microbiology].

Other names

stx1stx2Shiga-like toxin genesVerotoxin genesvtx

The stx genes encode Shiga toxins that inhibit host protein synthesis by depurinating the 28S rRNA of the 60S ribosomal subunit [StatPearls].