Bacteria as Allies

We are learning more and more about the benefits of bacteria. Certainly, with the help of fungi, bacteria play a vital role in breaking down and recycling dead organisms. Healthy internal tissues (e.g. blood, brain, muscle, etc.) are free of microorganisms, but skin & mucous membranes in our gastrointestinal tract, our respiratory tract, and our genito-urinary tract, are in contact with organisms in the environment, and these surfaces become colonized with many of these bacterial species. These bacteria that are regularly found at a given site are referred to as "normal flora." The normal flora of humans is consists of >200 species of bacteria. Their makeup depends on age, sex, stress, nutrition, etc. The table below shows a partial list of some of the more common bacteria regularly found in and on humans. The number of plus signs indicates their relative abundance. +/- indicates that the species may or may not be present.



These normal flora provide us with many benefits, which include:

Some data suggests that inappropriate use of antibiotics and the avoidance of microbes through disinfecting ourselves and our environment may have adverse effects on health. In fact, there is data to suggest that over-disinfection in children may increase their risk of autoimmune disease, obesity, and asthma. Here are several interesting links that provide some insights into this idea.

NPR Blog

This site provides an excellent perspective on the many benefits of bacteria. There is an 8 minute audio file that was aired on NPR, and there are many other interesting links.

Gut Bacteria May Affect Our Brain

alternative accessible content


Lewis Thomas

An excerpt from Lewis Thomas: "The Lives of a Cell - Notes of a Biology Watcher." Bantam Books, 1974. pp.88-89."Germs"

Babies Know: A Little Dirt Is Good for You

From The New York Times: Personal Health: by Jane E. Brody, Published: January 26, 2009

Jonathan Eisen: Meet Your Microbes

This is a TED talk in which microbiologist Jonathan Eisen discusses the benefits of microbes and presents some ideas about how we might use microbes to improve human health. (14:23)  

The Ecology of Disease

The Ecology of Disease is is an article by Jim Robbins from the New York Times. Robbins says:

"If we fail to understand and take care of the natural world, it can cause a breakdown of these systems and come back to haunt us in ways we know little about. A critical example is a developing model of infectious disease that shows that most epidemics — AIDS, Ebola, West Nile, SARS, Lyme disease and hundreds more that have occurred over the last several decades — don't just happen. They are a result of things people do to nature.

Disease, it turns out, is largely an environmental issue. Sixty percent of emerging infectious diseases that affect humans are zoonotic — they originate in animals. And more than two-thirds of those originate in wildlife."

Dirt in Our Diets

This is an OpEd piece from the New York Times on June 20, 2012.

Feces Infusion to Cure Overinfection With C. difficile

(report in New England Journal of Medicine, Jan. 16, 2013