Abundance of Enterobacteriaceae in the colon mucosa in diverticular disease.

Aim: To compare gut bacterial diversity and amount of Enterobacteriaceae in colonic mucosa between patients with and without diverticular disease (DD).

Methods: Patients in a stable clinical condition with planned elective colonoscopy were included. Blood samples and colon mucosa biopsies were collected at the colonoscopy. Study questionnaires including questions about gastrointestinal symptoms were completed by the patients and physicians. DNA from mucosa samples was isolated and the amount of Enterobacteriaceae was estimated using PCR assay. Terminal restriction fragment length polymorphism was applied to assess microbial diversity. Diversity was estimated by calculations of richness (number of terminal restriction fragments) and Shannon-Wiener and Simpson's indices.

Results: A total of 51 patients were included, 16 patients with DD [68 (62-76) years] and 35 controls [62 (40-74) years] without any diverticula. Patients with DD had significantly higher levels of Enterobacteriaceae than those without DD (P = 0.043), and there was an inverse relationship between the amount of Enterobacteriaceae and the Simpson's index (rs = -0.361, P = 0.033) and the Shannon-Wiener index (rs = -0.299, P = 0.081). The Simpson's index (P = 0.383), Shannon-Wiener index (P = 0.401) or number of restrictions fragments (P = 0.776) did not differ between DD and controls. The majority of patients experienced gastrointestinal symptoms, and 22 patients (43.1%) fulfilled the criteria for irritable bowel syndrome, with no difference between the groups (P = 0.212). Demography, socioeconomic status, lifestyle habits, inflammatory biomarkers, or symptoms were not related to the amount of Enterobacteriaceae or bacterial diversity.

Conclusion: Patients with DD had higher amount of Enterobacteriaceae in the colon mucosa compared to patients without diverticula.