The bacterial flora of the gastro intestinal (GI) tract may be involved in chronic inflammation and colon cancer and affected by antibiotics, cytotoxic drugs and radiotherapy, trauma and intensive care therapy. It is important to map the mucosa-associated flora in healthy individuals to clarify the pathogenic risk under stressed conditions. The aim was to achieve an overview of the mucosa-associated bacterial flora in the sigmoid colon by direct 16S rDNA identification by sampling nine 60-years old volunteers, without clinical symptoms or medication. The bacterial flora was estimated by sequence analysis of cloned 16S rDNA as enriched by PCR from biopsies. 26% of the clones had ≥99% similarity to known species (36% had ≥98% similarity). The largest number of identified clones was related to Escherichia coli, Bacteroides vulgatus and Ruminicoccus torques. Most frequently distributed between the volunteers were Bacteroides uniformis and Bacteroides vulgatus (7 individuals). Bacteroides caccae, Bacteroides distasonis, Bacteroides putredinis, Bacteroides thetaiotaomicron and Ruminicoccus torques were found in 5 persons. Opportunistic pathogens found in more than one individual were Bacteroides fragilis, Escherichia coli and Bilophila wadsworthia. Acinetobacter baumannii, Brachyspira aalborgi, Cardiobacterium hominis, Clostridium perfringens, Klebsiella pneumoniae and Veillonella parvula were found in single individuals. A majority of the individuals had a heterogeneous flora but in one person, 91% of the clones were related to E. coli. The GI-flora differs between healthy individuals in respect to both composition and diversity, and it can include several opportunistic pathogens.
|Number of pages||13|
|Journal||Preprint without journal information|
|Publication status||Unpublished - 2003|
Bibliographical noteThis work was run experimentally during 1998-2000 and the manuscript in its present form was finished 2002. The method of direct gene identification of bacteria in environmental samples by cloning of 16S rRNA genes was relatively new at that time, and the method as such, and the way the results were presented without a phylogenic analysis were called in question and given as the major reason for rejection by three different journals. Then, the manuscript was put aside, but in perspective of the fact that the method now is generally accepted and the work still has certain unique merits (relatively numerous and long sequences; samples in form of colonic biopsies from healthy 60 years old humans) it has been made public in LUP.
The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Applied Nutrition and Food Chemistry (011001300), Surgery Research Unit (013242220)
Subject classification (UKÄ)
- Nutrition and Dietetics
- direct gene identification
- colonic biopsies
- healthy humans
- colonic bacterial flora
- 16S rRNA gene
- 60 years old