Escherichia coliO157:H7 colonization in small domestic ruminants

Abstract

Enterohaemorrhagic Escherichia coli O157:H7 was first implicated in human disease in the early 1980s, with ruminants cited as the primary reservoirs. Preliminary studies indicated cattle to be the sole source of E. coli O157:H7 outbreaks in humans; however, further epidemiological studies soon demonstrated that E. coli O157:H7 was widespread in other food sources and that a number of transmission routes existed. More recently, small domestic ruminants (sheep and goats) have emerged as important sources of E. coli O157:H7 human infection, particularly with the widespread popularity of petting farms and the increased use of sheep and goat food products, including unpasteurized cheeses. Although the colonization and persistence characteristics of E. coli O157:H7 in the bovine host have been studied intensively, this is not the case for small ruminants. Despite many similarities to the bovine host, the pathobiology of E. coli O157:H7 in small domestic ruminants does appear to differ significantly from that described in cattle. This review aims to critically review the current knowledge regarding colonization and persistence of E. coli O157:H7 in small domestic ruminants, including comparisons with the bovine host where appropriate.

Enterohaemorrhagic, but not enteropathogenic, Escherichia coli infection of epithelial cells disrupts signalling responses to tumour necrosis factor-alpha

“…Enterohaemorrhagic Escherichia coli (EHEC), serotype O157 : H7 asymptomatically colonizes the gut of ruminants (La Ragione et al, 2009), but is a zoonotic infection linked to both food-and water-borne outbreaks of diarrhoea and haemorrhagic colitis in humans. EHEC O157 : H7 infection is the primary cause of diarrhoea-associated haemolyticuraemic syndrome, primarily afflicting children and the elderly (Tarr et al, 2005).…”

Distribution of Virulence Genes Related to Adhesions and Toxins in Shiga Toxin-Producing Escherichia coli Strains Isolated from Healthy Cattle and Diarrheal Patients in Japan

“…Cattle and other ruminants have been implicated as primary reservoirs of STEC O157:H7 as well as non-O157 STEC [8,16,17]. Previous studies estimated that about 28% cattle secrete STEC O157:H7 in their feces in the US [6].…”

An outbreak of caprine meningoencephalitis due to Escherichia coli O157:H7

“…2 In addition, enteric infections of newborn and young goats associated with E. coli O157:H7 as a result of fecal-oral contamination have been extensively reported. 9 Although colonization and persistence of STEC in the alimentary tract of young ruminants usually results in a hemorrhagic diarrhea that can be fatal, it is well documented that systemic infections due to the penetration of the gut epithelium also occur. 7 This known potential for systemic infection matches the results of the histologic findings and bacteriology culture results for the 3 diseased animals examined in the current study.…”