This bacterial genomic contribution is critical for human survival. Genes carried by bacteria in the gastro-intestinal tract, for example, allow humans to digest foods and absorb nutrients that otherwise would be unavailable. Moreover, the microbes produce beneficial compounds, like vitamins and anti-inflammatories that our genome cannot produce.
Researchers were surprised to discover that the distribution of microbial metabolic activities matters more than the species of microbes providing them. In the healthy gut, for example, there will always be a population of bacteria needed to help digest fats, but it may not always be the same bacterial species carrying out this job.
Moreover, the components of the human microbiome clearly change over time. When a patient is sick or takes antibiotics, the species that makeup of the microbiome may shift substantially as one bacterial species or another is affected. Eventually, however, the microbiome returns to a state of equilibrium, even if the previous composition of bacterial types does not.
For example, researchers at the Baylor College of Medicine in Houston compared changes in the vaginal microbiome of 24 pregnant women with 60 women who were not pregnant and found that the vaginal microbiome undergoes a dramatic shift in bacterial species in preparation for birth, principally characterized by decreased species diversity.
A newborn is a bacterial sponge as it populates its own microbiome after leaving the sterile womb; passage through the birth canal gives the baby its first dose of microbes, so it may not be surprising that the vaginal microbiome evolved to make it a healthy passage.
Louis examined the nasal microbiome of children with unexplained fevers, a common problem in children under 3 years of age. Nasal samples from the feverish children contained up to five-fold more viral DNA than children without fever, and the viral DNA was from a wider range of species. Previous studies show that viruses have ideal temperature ranges in which to reproduce.
Fevers are part of the body's defense against pathogenic viruses, so rapid tests for viral load may help children avoid inappropriate treatment with antibiotics that do not kill the viruses but may harm the child's healthy microbiome.
These are among the earliest clinical studies using microbiome data to study its role in specific illnesses. NIH has funded many more medical studies using HMP data and techniques, including the role of the gut microbiome in Crohn's disease, ulcerative colitis and esophageal cancer; skin microbiome in psoriasis, atopic dermatitis and immunodeficiency; urogenital microbiome in reproductive and sexual history and circumcision; and a number of childhood disorders, including pediatric abdominal pain, intestinal inflammation, and a severe condition in premature infants in which the intestine actually dies.
Craig Venter Institute, Rockville, MD, and lead co-author of the Nature paper on the framework for current and future human microbiome research. The NIH Common Fund also invested in a series of studies to evaluate the ethical, legal and social implications of microbiome research. While the results of these studies are yet to be published, a number of important issues already have been identified, ranging from how products designed to manipulate the microbiome — such as probiotic concoctions that include live microorganism believed to benefit the body — might be regulated, to whether individuals should begin to consider storing their microbiome while healthy.
The consortium has coordinated research to avoid duplication of effort and insured rapid release of molecular and clinical data sets. Are they friendly? Or can they make us ill? How do they get in? What is their role in the body? Bacteria are tiny living microorganisms that are too small to be seen by the naked eye. They are a 1, times smaller than a pencil tip. We have to use an instrument called a microscope, which makes the image of the bacteria big enough to be seen. There are many different kinds of bacteria with diverse shapes and sizes.
Some look like a baseball bat, others are round like a basketball but millions of times smaller Figure 1. Bacteria live on the skin, inside the nose, in the throat, in the mouth, in the vagina, and in the gut. The majority of the bacteria found in the body live in the human gut. There are billions of bacteria living there Figure 2.
We call the group of all the microbes found in the body the human microbiota [ 1 ]. These microorganisms colonize the body, which means that they usually do not cause any harm. When a microorganism causes sickness, that is called an infection. We begin to be colonized by bacteria during birth.
During the birth process and immediately after birth, we get our first microorganisms. All babies also acquire bacteria from the skin of the nurses and medical doctors and the environment they live in.
After babies begin to eat, they get microbes from their diet. In the first days of life, the type of the microorganisms that colonize their intestines will be different, depending whether the baby is breast feeding or drinking formula.
As babies grow, they get microorganisms from the solid food they eat, from crawling on the floor, from putting their hands in their mouths, from licking toys, and from many other sources! The microbes that live in the human body change during our growth, until we are 3 years old. At that point, the microbiota becomes more or less stable until adult life.
Each individual has his or her own microbiota, which depends in part, but not only, on the types of food eaten, the environment where the person lives, and the other people and animals that the person interacts with Figure 3 [ 2 , 3 ].
When we mention bacteria in the human body, you might immediately think of a disease, called a bacterial infection. At some point in your life, you have probably had an infection that was treated by antibiotics prescribed by your doctor. Antibiotics are medicines that kill or prevent the growth of bacteria.
However, the majority of the microbes are harmless and actually help to maintain our health. The microbes of the skin, mouth, and nose fight against bad bacteria that want to enter the body to cause disease. These good bacteria act like guards that keep away the harmful bacteria that make us sick.
The bacteria that colonize the vagina are another example of good bacteria. They maintain an acidic environment in the vagina that prevents the growth of other microorganisms that might cause disease.
Disease-causing microorganisms are called pathogens. Even though most of the time they are harmless or even helpful, in certain conditions some of the bacteria that are part of the human microbiota can harm us. For example, bacteria that live on the skin can become a problem. If you cut yourself, the bacteria that live on the surface of your skin may be able to enter into your body through the cut, getting in where they do not belong. In this instance, these bacteria sometimes might be harmful to the body and trigger an infection.
Symptoms of an infection include pain, swelling, redness, and fever. Another example of how the microbiota can harm us is when you let too many bacteria accumulate in your mouth.
What's a GMO? What's a Genome? Beneficial Bacteria Bacteria are the most abundant form of life on the planet. You also have good bacteria within and on your own body. Did you know that you have ten times more bacterial cells in your body than you have human cells?
Most of these bacteria are in your digestive system. There, they help to digest substances that the human body cannot break down, like many carbohydrates and things called short chain fatty acids. It is important that we keep this population healthy. Eating probiotics can help to replenish good gut bacteria. On the other hand, taking unnecessary antibiotics can hurt this community. When this happens, we often get symptoms like diarrhea or stomach pain.
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