Pathogens in Crohn's Disease: The Role of Adherent Invasive Escherichia coli

Abstract

In Crohn's disease (CD), gut dysbiosis is marked by the prevalence of pathogenic bacterial species. Although several microbes have been reported as risk factors or causative agents of CD, it is not yet clear which is the real trigger of the disease. Thirty years ago, a new pathovar of <i>Escherichia coli </i>strain was isolated in the ileal mucosa of CD patients. This strain, called adherent invasive <i>E. coli</i> (AIEC), for its ability to invade the intestinal mucosa, could represent the causative agent of the disease. Several authors studied the mechanisms by which the AIEC penetrate and replicate within macrophages, and release inflammatory cytokines sustaining inflammation. In this review we will discuss about the role of AIEC in the pathogenesis of CD, the virulence factors mediating adhesion and invasion of AIEC in mucosal tissue, the environmental conditions improving AIEC survival and replication within macrophages. Finally, we will also give an overview of the new strategies developed to limit AIEC overgrowth.

Antibiotic Therapy for Active Crohn’s Disease Targeting Pathogens: An Overview and Update

“…In the last decades, several pathogens (Table 1) have been found to have a role in the pathogenesis of CD [8,9], but only E. coli [10][11][12][13] and Mycobacterium avium paratubercolosis (MAP) [14,15] have aroused interest due to their strong association with CD pathogenesis. In 1998, a new pathovar strain of E. coli, defined as adherent invasive E. coli (AIEC), was isolated from the ileal mucosa of CD patients, as that was assumed to be a potential etiological source of the disease [16].…”