AB5 Enterotoxin-Mediated Pathogenesis: Perspectives Gleaned from Shiga Toxins

Abstract

Foodborne diseases affect an estimated 600 million people worldwide annually, with the majority of these illnesses caused by Norovirus, Vibrio, Listeria, Campylobacter, Salmonella, and Escherichia coli. To elicit infections in humans, bacterial pathogens express a combination of virulence factors and toxins. AB5 toxins are an example of such toxins that can cause various clinical manifestations, including dehydration, diarrhea, kidney damage, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Treatment of most bacterial foodborne illnesses consists of fluid replacement and antibiotics. However, antibiotics are not recommended for infections caused by Shiga toxin-producing E. coli (STEC) because of the increased risk of HUS development, although there are conflicting views and results in this regard. Lack of effective treatment strategies for STEC infections pose a public health threat during outbreaks; therefore, the debate on antibiotic use for STEC infections could be further explored, along with investigations into antibiotic alternatives. The overall goal of this review is to provide a succinct summary on the mechanisms of action and the pathogenesis of AB5 and related toxins, as expressed by bacterial foodborne pathogens, with a primary focus on Shiga toxins (Stx). The role of Stx in human STEC disease, detection methodologies, and available treatment options are also briefly discussed.

High Prevalence and Persistence of Escherichia coli Strains Producing Shiga Toxin Subtype 2k in Goat Herds

“…Previous studies have reported differences between Stx1/Stx2 types and subtypes in terms of host specificity and binding strength ( 6 , 21 ). One Stx2k variant was reported to be less toxic than Stx2a but similar in receptor-binding preference, acid tolerance, and thermostability in a Vero cell assay ( 22 ).…”

Enterohemorrhagic Escherichia coli and a Fresh View on Shiga Toxin-Binding Glycosphingolipids of Primary Human Kidney and Colon Epithelial Cells and Their Toxin Susceptibility

“…The administration of antibiotics in EHEC infections was and remains controversial because of concerns about triggering HUS by increasing Stx production [285][286][287]. Stxs are encoded by genes located on genomes of lambdoid prophages and certain antibiotics stimulate their induction leading to enhanced production of Stxs [288].…”

Eating Animal Products, a Common Cause of Human Diseases

“…While numerous types of bacteria cause food poisoning, several of these organisms cause most of the illnesses, and only these will be discussed here. Escherichia, Shigella, Salmonella, Vibrio and Campylobacter species (e.g., Escherichia coli, Shigella flexneri; S. typhimurium; Vibrio parahaemolyticus; and C. jejuni, respectively) are all related Gram-negative proteobacteria that are primary causes of variant forms of food poisoning [Biernbaum and Kudva, 2022]. Escherichia, Shigella and Salmonella are very closely related genera within the gamma-proteobacteria, and E. coli, the most extensively studied and best understood organism on Earth, is among the primary causes of infant mortality worldwide, past and present.…”

“…Also, remember that vomiting and diarrhea can be severely dehydrating and may require medical attention. Washing of foodstuffs and sterilization should be undertaken in these instances [Filip et al, 2021;Biernbaum and Kudva, 2022]. A little care can go a long way!…”