Overview of the Human Microbiome

Planet You: Bacteria Have You Covered

A Human What? The Human Microbiome

Trillions of individual bacteria, viruses and other microscopic creatures live on the surface and inside of the human body and make up the human microbiome.

Bacteria and Health

Scientists have known for many years that bacteria play an important role in health and a few, known as pathogens, cause disease. Among the tens of thousands of known bacterial species in the world, however, only about 100 are pathogens. Scientists are now learning the important role of bacteria in protecting health.

Getting to Know You

Learning about what makes up the microbiome is, in a way, like getting to know ourselves. Microorganisms live everywhere in the human body – in any person there are at least ten times as many bacterial cells as human cells. More than 1,000 species of bacteria live in and on us. At least 300 species of bacteria can be found just in a person's mouth. The metagenome (all of the genetic material in our body) contains 100 times more microbial genes than human genes.

What we Know

Here's what's known about the role of bacteria in maintaining health. Some bacteria help protect us from other pathogens, in some cases literally taking up space so that harmful bacteria cannot set up residence. Some bacteria help us absorb nutrients and others serve as indicators of the status of our health. Changes and perturbations in a person's microbiome have been associated with a number of diseases and conditions such as Crohn's disease, bacterial vaginosis and obesity.

What Scientists are Doing

by the Canadian Institutes of Health Research (CIHR) are participating in the International Human Microbiome Project. Because of the scale of this undertaking, some researchers have described the initiative as a second Human Genome Project. But it's not going to be an easy job. It's estimated that between 20 to 60 % of human-associated bacteria, depending on body site, cannot be grown in the lab using conventional techniques.

How Can We Use This Information?

Knowledge gained from research on the human microbiome will increase our understanding of the associations between our microbial flora and our health and may provide insight on how manipulations of microbiome can be used to prevent and treat disease.

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