Attaching-effacing Escherichia coli Infections in Cattle

Abstract

Diarrheagenic Escherichia coli are now broadly placed into 6 classes based on virulence mechanisms. One of these classes, enterotoxigenic E coli, is the most common cause of diarrhea in beef and dairy calves in the first 4 days of life. Two other diarrheagenic classes, enterohemorrhagic E coli (EHEC) and enteropathogenic E coli (EPEC), are important causes of disease in human beings, but less well substantiated causes of diarrhea in calves. E coli strains that cause hemorrhagic colitis and hemolytic uremic syndrome in humans, express high levels of Shiga toxin, cause attaching-effacing (A/E) lesions in intestinal epithelial cells, and possess a specific 60-MDa EHEC plasmid are known as EHEC. One feature EHEC and EPEC have in common is the causation of intestinal epithelial lesions known as attaching and effacing (A/E). Attaching-effacing E coli (AEEC) is a designation for those E coli strains known to cause A/E lesions or at least carry the genes for this trait, and therefore include organisms that fall into either the EHEC or EPEC classes. Because cattle are carriers of many different serotypes of EHEC, much emphasis has been placed on the public health and food safety concerns associated with the fecal shedding of these organisms. However, much less emphasis has been given to their roles as diarrheagenic pathogens of cattle. The goal of this article is to address the question of pathogenicity, with a review that focuses on the results of studies of natural and experimental infections with these organisms. The authors conclude that there is overwhelming evidence that many different serogroups of AEEC are diarrheagenic pathogens of calves.

Escherichia coli virulence factors

“…AE lesions are the results of a profound disorganization of the actin filaments of the eukaryotic cell skeleton and of their re-organization beneath the intimately attached bacteria to form pedestals (Nataro and Kaper, 1998;Clarke et al, 2003;Kaper et al, 2004;Garmendia et al, 2005;Mainil and Daube, 2005;Moxley and Smith, 2010;Schmidt, 2010;Bolton, 2011).…”

“…They are grouped into several functional gene clusters, the most important being: the espA, B, D genes coding for the type 3 secretion system (T3SS) structural proteins (or injectisome); the esc/sep genes coding for the anchor structure of the injectisome within the outer and inner bacterial membranes; the tir and several other genes coding for the type 3-secreted effectors into the eukaryotic cells; and the eae gene coding for the intimin adhesin located within the bacterial outer membrane (see Section 2.3) (Clarke et al, 2003;Garmendia et al, 2005;Mainil and Daube, 2005;Moxley and Smith, 2010;Schmidt, 2010;Bolton, 2011).…”

Detection of virulence and antimicrobial resistance genes in Escherichia coli isolates from diarrhoiec dogs in Iran

“…This nullifies possible involvement of EPEC/ AEEC strains in diarrhoeal disease in the sampled dogs (Bentancor et al 2007, Shahrani et al 2014. EPEC strains are defined as eae-harbouring diarrhoeagenic E. coli that possess the ability to form A/E lesions on intestinal cells and that do not possess shiga-like toxin encoding genes (Moxley andSmith 2010, Shahrani et al 2014). EPEC strains habouring the plasmid-encoded bundle forming pilli (bfp) gene, are regarded as typical EPEC (tEPEC) while bfp non-habouring strains are atypical EPEC (aEPEC) (Moxley andSmith 2010, Ali andMetwaly 2015).…”

“…EPEC strains are defined as eae-harbouring diarrhoeagenic E. coli that possess the ability to form A/E lesions on intestinal cells and that do not possess shiga-like toxin encoding genes (Moxley andSmith 2010, Shahrani et al 2014). EPEC strains habouring the plasmid-encoded bundle forming pilli (bfp) gene, are regarded as typical EPEC (tEPEC) while bfp non-habouring strains are atypical EPEC (aEPEC) (Moxley andSmith 2010, Ali andMetwaly 2015). Since this study did not detect EPEC strains, the presence of bfp gene in the isolates was not investigated.…”

Isolation and Molecular Characterization of ETEC and NTEC Escherichia coli from Cattle Farm With Reference to Virulence Marker Gene

“…Among the six recognized diarrhoeagenic categories of E. coli ETEC is the most common, particularly in the developing world (Osman et al, 2012). Enterotoxigenic E. coli (ETEC) is a major pathogen of animals, being responsible for diarrhea in calves resulting significant financial losses (Zinnah et al, 2007) and the major enteropathogen associated with neonatal calf diarrhoea worldwide (Moxley and Smith ,2010). …”