Background: The majority of Crohn's disease (CD) patients undergo at least one intestinal resection during the course of their disease. Since surgery is not a curative treatment, postoperative recurrence (RPO) is a major issue in these patients, as up to 70% of patients have endoscopic RPO within one year of surgery. The aim was to determine whether the presence of adherent and invasive Escherichia coli (AIEC) bacteria at the time of surgery was associated with endoscopic RPO at 6 months.
Methods: REMIND group has established a homogeneous, prospective, multicenter cohort (POP-REMIND) of operated CD patients. Samples was performed on the surgical specimen (M0) and at endoscopy (M6), and stored centrally in a bio-bank. The inclusion criteria were: age ≥18 years, ileal or ileocaecal CD requiring intestinal resection. Post-operative treatment was prescribed according to a pre-established algorithm. Clinical outcome, therapeutic, biological and endoscopic data (Rutgeerts score) were collected 6 months after surgery. Clinical factors (demographic variables, phenotypic and postoperative treatments) associated with endoscopic recurrence were investigated by univariate analysis and logistic (multivariate) regression. The search for AIEC bacteria was carried out by culturing and investigating the characteristics of adhesion, invasion in Int-407 cells, and survival within THP-1 macrophages.
Results: Presence of AIEC strains was determined on the surgical specimen in 226 patients; 30 had a positive AIEC status. Descriptive analysis of the population at M0 showed that the presence of AIEC was inversely associated with a penetrating phenotype of the disease (13% for AIEC+ versus 38% for AIEC− patients, p=0.005). On the other hand, presence of AIEC on the surgical specimen was not correlated with age, disease duration, smoking, previous surgical resection and with preoperative anti-TNF exposure. Of the 226 patients included, 170 had a postoperative colonoscopy (M6). At time of surgery, only 26 of the 170 patients (15.3%) were carriers of AIEC. Presence of AIEC on the surgical specimen was not associated with an increased risk of post-operative recurrence (i1-i4). However, the presence of AIEC on the surgical specimen was predictive of severe endoscopic post-operative recurrence (i3 and i4): 10 among 26 patients AIEC+ (38%) versus 24/143 (17%) for AIEC−; p=0.01). After adjusting for age, sex, pre- or post-operative exposure to TNF antagonists and antibiotics, the presence of AIEC on the surgical specimen was associated with severe endoscopic recurrence i3-i4 (OR =3.42 CI95% [1.31–8.84], p=0.011).
Conclusions: The presence of AIEC on the surgical specimen was an independent risk factor for severe endoscopic post-operative recurrence of Crohn's disease.