Instability of the faecal microbiota in diarrhoea-predominant irritable bowel syndrome.

The irritable bowel syndrome (IBS) is a functional gastrointestinal disorder with a largely unknown aetiology and a wide range of symptoms. Most cross-sectional studies carried out so far suggest subtle alterations in the structure of the intestinal microbiota that are barely reproduced, partly because of the high inter-subject variation in the community composition and disorder-specific features. We performed a longitudinal study to explore the within-subject variation in the faecal microbiota in two patients with IBS classified into the diarrhoea subtype and the healthy spouse of one of them.

Structural alterations of faecal and mucosa-associated bacterial communities in irritable bowel syndrome.

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder in western countries. Previous studies on IBS, mostly based on faecal samples, suggest alterations in the intestinal microbiota. However, no consensus has been reached regarding the association between specific bacteria and IBS.

Daily follow-up of bacterial communities in the human gut reveals stable composition and host-specific patterns of interaction.

In the last decade, an extensive effort has been made to characterize the human intestinal microbiota by means of SSU rRNA gene sequence and metagenomic analysis. Relatively few studies have followed intestinal bacterial communities over time to assess their stability in the absence of perturbation. In this study, we have monitored the faecal bacteria of three healthy subjects during 15 consecutive days.

Bacteria associated with Copestylum (Diptera, Syrphidae) larvae and their cactus host Isolatocereus dumortieri.

We describe the gut bacterial diversity inhabiting two saprophagous syrphids and their breeding substrate (decayed tissues of the columnar cactus Isolatocereus dumortieri). We analyzed the gut microbiota of Copestylum latum (scooping larvae that feed on decayed cactus tissues) and Copestylum limbipenne (whose larvae can also feed on semiliquid tissues) using molecular techniques. DNA was extracted from larval guts and cactus tissues.

Metatranscriptomic approach to analyze the functional human gut microbiota.

The human gut is the natural habitat for a large and dynamic bacterial community that has a great relevance for health. Metagenomics is increasing our knowledge of gene content as well as of functional and genetic variability in this microbiome. However, little is known about the active bacteria and their function(s) in the gastrointestinal tract.

Assessing gut microbial diversity from feces and rectal mucosa.

Gut microbiota is the most complex bacterial community in the human body and its study may give important clues to the etiology of different intestinal diseases. Most studies carried out so far have used fecal samples, assuming that these samples have a similar distribution to the communities present throughout the colon. The present study was designed to test this assumption by comparing samples from the rectal mucosa and feces of nine healthy volunteers by sequencing libraries of 16S rRNA genes.