Pathogenesis of Adherent–Invasive Escherichia Coli

Abstract

The etiology of Crohn's disease (CD) is complex and involves both host susceptibility factors (i.e., the presence of particular genetic alleles) and environmental factors, including bacteria. In this regard, adherent-invasive Escherichia coli (AIEC), have recently emerged as an exciting potential etiological agent of CD. AIEC are distinguished from commensal strains of E. coli through their ability to adhere to and invade epithelial cells and replicate in macrophages. Recent molecular analyses have identified genes required for both invasion of epithelial cells and replication in the macrophage. However, these genetic studies, in combination with recent genome sequencing projects, have revealed that the pathogenesis of this group of bacteria cannot be explained by the presence of AIEC-specific genes. In this article, we review the role of AIEC as a pathobiont in the pathology of CD. We also describe the emerging link between AIEC and autophagy, and we propose a model for AIEC pathogenesis.

Adherent‐invasive Escherichia coli (AIEC): Cause or consequence of inflammation, dysbiosis, and rupture of cellular joints in patients with IBD?

“…This process prevents the immune system from activating a proinflammatory response against commensal bacteria, while still maintaining the ability to protect against pathogens. When intestinal inflammation occurs, the mucosal barrier is interrupted and the specific epithelial receptors are expressed abnormally; a consequence of this is a greater intestinal permeability and susceptibility to the pathogenesis of AIEC (Antoni, Nuding, Wehkamp, & Stange, 2014;Benjamin, Makharia, Ahuja, Kalaivani, & Joshi, 2008;Sasaki et al, 2007;Smith, Thompson, O'Driscoll, & Clarke, 2013;Wine, Ossa, Gray-Owen, & Sherman, 2010). In the first moments of interaction, the ability of adhesion and invasion is given by flagella, Type 1 fimbria, outer membrane proteins (OmpCs) and…”

IBD: Microbiota Manipulation through Diet and Modified Bacteria

“…Bacterial colonisation of the mucus layer or the sub-mucus niche is rare in the healthy colon but much commoner in IBD, particularly CD, where colonisation of the mucosa is also found in the terminal ileum. The most consistent abnormality is an increase of mucosa-associated Escherichia coli in CD patients [16]. The recent paediatric CD microbiota study also showed an increase in mucosa-associated species of Fusobacterium , Haemophilus and Veillonella [15].…”

NOD2 induces autophagy to control AIEC bacteria infectiveness in intestinal epithelial cells

“…Among the latter, a particular attention has been focused on adherent-invasive E. coli (AIEC), a group featured by their ability to adhere and invade intestinal epithelial cells and survive within mature phagolysosomes of macrophages [21][22][23][24]. These strains are more abundant in CD patients [19,25,26] and are thought to have a role in the early stages of disease onset [27,28]. Recently, defects in autophagy have been related to an increased persistence of AIEC inside macrophages [29,30].…”