Bacteria, and then there were three. A new joint team of scientists from both Japan and Europe have determined that there are three bacteria groups in a person, which is teaming with microorganisms and microbes. Each group is named for the bacteria most commonly found in the group and it seems everyone falls into one of these leading categories.
First there are the Bacteroides. Bacteroides are commonly found in the human intestine where they have a symbiotic host-bacterial relationship with humans. They assist in breaking down food and producing valuable nutrients and energy that the body needs. However, when Bacteroides are introduced to parts of the body other than the gastrointestinal area, they can cause or exacerbate abscesses and other infections.
Next comes the Prevotella group or enterotype. These are among the most numerous microbes culturable from the rumen and hind gut of cattle and sheep, where they help the breakdown of protein and carbohydrate foods. They are also present in humans, where they can be opportunistic pathogens. Prevotella, credited interchangeably with Bacteroides melaninogenicus, has been a problem for dentists for years. As a human pathogen known for creating periodontal and tooth problems, Prevotella has long been studied in order to counteract its pathogenesis (AAP).
Finally, there is the Ruminococcus group, and was the most commonly dominant type found in the study. These organisms allow their hosts to digest cellulose. Ruminococcus’ cellulose degradation abilities are currently a major area of study. By understanding how these organisms degrade cellulose, farmers may be able to make advances in animal productivity. In addition, this knowledge could have an environmental impact. It has been suggested that scientists could develop better methods of recycling paper and wood materials.
Previous studies had suggested that each person may have their own unique mix of intestinal microbes, but the new study took a closer look into the structure of each human examined. Identifying distinct conglomerates of bacteria will aid scientists in determining if certain mixes of microbes contribute to health and disease according to comments on the research.
Species mix wasn’t linked to any particular human trait, certain groups of genes or biochemical functions carried out by the bacteria did match up with traits. How bacteria use their genes is probably more important than which species are present.
Jeremy Nicholson of Imperial College London says:
“There’s this obsession with microbial speciation, which bugs do what…but what is actually important is the capabilities of the microbial community as a whole.”
The researchers don’t yet know if a person’s enterotype changes over time or stays the same throughout life, or if certain enterotypes predispose people for diseases. However, the team does have a host of yet unpublished results that link specific gut-bacteria species to individual characteristics.
Researchers have only recently begun to appreciate the importance of the bacterial cells that grow on and in our bodies, outnumbering our own cells by about ten to one. In rodents, gut microbes are known to influence weight and immunity against disease.
In the United States, the Human Microbiome Project is aiming to catalogue all the microbes living in our nose, mouth, skin, gut, and urinary and genital tracts and in Europe, the Metagenomics of the Human Intestinal Tract (MetaHIT) Consortium is focusing on the gut itself.
Written by Sy Kraft