Mucosa-Associated Bacteria in the Human Gastrointestinal Tract Are Uniformly Distributed along the Colon and Differ from the Community Recovered from Feces

Abstract

The human gastrointestinal (GI) tract harbors a complex community of bacterial cells in the mucosa, lumen, and feces. Since most attention has been focused on bacteria present in feces, knowledge about the mucosaassociated bacterial communities in different parts of the colon is limited. In this study, the bacterial communities in feces and biopsy samples from the ascending, transverse, and descending colons of 10 individuals were analyzed by using a 16S rRNA approach. Flow cytometric analysis indicated that 10 5 to 10 6 bacteria were present in the biopsy samples. To visualize the diversity of the predominant and the Lactobacillus group community, denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA gene amplicons was performed. DGGE analysis and similarity index comparisons demonstrated that the predominant mucosaassociated bacterial community was host specific and uniformly distributed along the colon but significantly different from the fecal community (P < 0.01). The Lactobacillus group-specific profiles were less complex than the profiles reflecting the predominant community. For 6 of the 10 individuals the community of Lactobacilluslike bacteria in the biopsy samples was similar to that in the feces. Amplicons having 99% sequence similarity to the 16S ribosomal DNA of Lactobacillus gasseri were detected in the biopsy samples of nine individuals. No significant differences were observed between healthy and diseased individuals. The observed host-specific DGGE profiles of the mucosa-associated bacterial community in the colon support the hypothesis that host-related factors are involved in the determination of the GI tract microbial community.

Dynamic changes of the luminal and mucosa-associated gut microbiota during and after antibiotic therapy with paromomycin

“…Mucosal microbiota is in contact with the gut-associated lymphoid tissue and is thus likely to be more important to the host. 4,9 This is supported by the finding of Ott et al 17 showing by Single Strand Conformational Polymorphism analysis that mucosa-associated microbiota differ from fecal communities in healthy individuals. Moreover, it is of importance to take the active microbiota into account, as only they contribute to metabolic turnover and were shown to differ from present microbiota in healthy and diseased people.…”

“…[1][2][3][4][5] Gut microbiota show considerable compositional variation between individuals, but remain relatively stable over time. [6][7][8][9] This specific microbial composition can be disrupted by external factors, such as antibiotic (AB) treatment. As most antibiotics eliminate pathogenic and beneficial host-associated microbes alike, their usage can lead to a dramatic compositional imbalance of the gut microbiota.…”

Fusobacterium nucleatum associates with stages of colorectal neoplasia development, colorectal cancer and disease outcome

“…Previously, bacterial communities in the colon have also been found to differ significantly to those in the faeces [36]. The potential of Fn as a non-invasive CRC screening biomarker needs to be tested in a large study.…”

Inferred metagenomic comparison of mucosal and fecal microbiota from individuals undergoing routine screening colonoscopy reveals similar differences observed during active inflammation

“…8 Although the luminal microbiota may simply be a numerical transformation of the mucosal microbiome, 9 comparisons of mucosal and fecal samples have shown that these 2 intestinal compartments have significantly different microbial communities. [10][11][12] Next generation 16S rRNA sequencing reveals alterations to bacterial taxa, but not changes to the metabolic activity and function of microbial communities. Shotgun metagenomic studies of total bacterial gene content for functional analysis are often limited by insufficient material and host DNA contamination (e.g., in biopsy samples).…”