Intimate Attachment of Escherichia coli O157:H7 to Urinary Bladder Epithelium in the Gnotobiotic Piglet Model

Abstract

Enterohemorrhagic Escherichia coli (EHEC), a pathogenic subset of Shiga toxin-producing E. coli (STEC), is an important cause of hemorrhagic colitis and hemolytic-uremic syndrome (HUS), and a rare cause of urinary tract infections (UTIs) with associated HUS. EHEC strains attach intimately to intestinal epithelium with formation of actin pedestals (attaching-effacing (A/E) lesions); however, the mechanism of EHEC attachment to the uroepithelium is unknown. We conducted a retrospective study on archived urinary bladder specimens from gnotobiotic piglets that naturally developed cystitis associated with EHEC O157:H7 infection following oral inoculation and fecal shedding. Paraffin-embedded bladder tissues from three piglets with cystitis and immunohistochemical evidence of EHEC O157:H7 adherence to the uroepithelium were processed for and examined by transmission electron microscopy. EHEC O157:H7 bacteria were found in one of three piglets, intimately attached to pedestals on the apical surfaces of the superficial urothelium (umbrella cells). Cystitis was significantly associated with the length of survival of the piglets post-inoculation (p = 0.0339; estimated odds ratio = 2.6652). This is the first report of E. coli causing A/E-like lesions in the uroepithelium, and also evidence of the utility of the gnotobiotic piglet as a model for studies of the pathogenesis of EHEC UTIs.

Review of major meat-borne zoonotic bacterial pathogens

“…Currently, there are 174 Pathogenic E. coli serotypes are usually associated with diarrhea or intestinal illnesses, but some strains of E. coli can also cause non-intestinal diseases. The primary source of this pathogen is the animal population, which is transferred to humans through animal products (23). Since the human food chain remains the primary transmission route for E. coli O157:H7 infection in humans, it is essential to stress the role that an intermediate habitat (i.e., a natural environment, in particular, the human food chain) would play in the fate of the clinical strains (24).…”

Meat Borne Diseases

“…Enterohemorrhagic E coli (EHEC) causes haemorrhagic colitis or haemolyticuremic syndrome (HUS) [33].…”

Meat Borne Bacterial Pathogens

“…There are 174 somatic-antigens, 53 flagellar-antigens and 80 capsularantigens (Tuo et al 2020). The most of serotypes of E. coli are responsible for causing diarrhea or intestinal diseases, while others are responsible for causing non-intestinal diseases (Chitarra et al 2014;Moxley et al 2020). Animals act as primary reservoirs for this bacterium and the pathogen can be transferred to humans via animal products that act as vehicle, or by direct contact (Avery et al 2004;Roche et al 2010).…”