Gut colonization with extended-spectrum β-lactamase-producing Enterobacteriaceae may increase disease activity in biologic-naive outpatients with ulcerative colitis: an interim analysis.

Certain Enterobacteriaceae strains have been associated with the development of ulcerative colitis (UC). Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae are the most commonly found multi-drug-resistant (MDR) bacteria colonizing the gut in UC patients and might trigger a more severe disease activity in UC patients. The aim of this study was to evaluate whether disease activity is higher in UC patients with gut colonization with ESBL-producing Enterobacteriaceae. A cross-sectional, pilot study was carried out in a tertiary medical center in Latvia. Demographic data were collected; UC disease activity and extent were evaluated according to the full Mayo score, Montreal classification, and adapted Truelove and Witt's index. Rectal swabs with fecal biomaterial were collected, ESBL-producing Enterobacteriaceae were isolated, and bacterial plasmid genes responsible for ESBL production, blaCTX-M, blaTEM, and blaSHV, were detected. UC disease activity was compared in patients with and without gut colonization with ESBL-producing Enterobacteriaceae. A total of 65 patients with UC were included in the initial analysis. Gut colonization with ESBL-producing Enterobacteriaceae was found in seven (11%) patients - mostly Escherichia coli [5 (71%)] containing the blaCTX-M bacterial plasmid gene. Patients with gut colonization with ESBL-producing Enterobacteriaceae had more severe disease compared with patients without gut colonization according to the full Mayo score (5.86 vs. 3.40; P=0.015), Montreal classification (moderate disease vs. clinical remission; P=0.031), and adapted Truelove and Witt's index (moderate disease vs. mild disease; P=0.008). Gut colonization with ESBL-producing Enterobacteriaceae may increase UC disease activity. Further research is needed to analyze the possible confounding factors that could contribute toward this outcome.