Background: The normal colonic microbiota is associated with the etiology of ulcerative colitis (UC). Several bacterial species
are associated with the initiation and amplification of disease process. However, the etiology and mechanism of UC are poorly
understood. The present study aimed to investigate, characterize, and compare the main composition of the mucosa-associated
intestinal microflora in colonoscopic biopsy specimens of UC and non-UC patients.
Methods: Aerobic and facultative-anaerobic mucosa-associated bacteria were isolated and diagnosed from colonoscopic biopsy
specimens of 40 UC patients and 40 patients without UC. Patients were selected as control from the same centers and colonoscopy
was carried out for other reasons (mainly colorectal screening). Isolation and characterization for aerobic and facultative-anaerobic
intestinal bacteria were carried out by conventional culture techniques. DNA extraction from biopsies and polymerase chain
reaction (PCR) amplification of bacterial 16S rRNA with gene-targeted and species-specific primers was performed for detection
of anaerobic bacterial species.
Results: Several species of mucosa-associated aerobic and facultative anaerobic bacteria were found in biopsy specimens and
there were no significant differences between UC patients and non-UC patients. Our investigation for detection of the anaerobic
intestinal flora showed Faecalibacterium prausnitzii, Prevotella, and Peptostreptococcus productus were the predominant
microflora in controls and have significant differences (P = 0.002, 0.025 and 0.039, respectively).
Conclusion: This is the first investigation of the intestinal mucosa-associated microflora in patients with UC in Iran. These results,
although limited by sample size, allow a better understanding of changes in mucosa-associated bacterial flora in these patients,
showing that decrease of Faecalibacterium prausnitzii, Provetella, and Peptostreptococcus productus in the intestinal tract may
translate into a reduction in the important role of this beneficial bacterial species, which can lead to reduced protection of the gut
mucosa and UC development.