The Human Microbiome Project is an NIH-sponsored initiative with the goal of identifying all of the many kinds of micro-organisms that we harbor in our bodies as healthy individuals. This is an interesting project for a number of reasons. First and foremost, because we have long assumed that micro-organisms are present only when we are sick – not healthy. Also, what we learn from this project can have a great impact on how we use antibiotics to treat many of the infections we get that do make us ill (often demanding them as patients even when they will do no good as when we have a viral infection like flu or the common cold). Lastly, we are now learning that alterations in the microbiome of our gut or elsewhere may contribute to more subtle changes in our health, like the incidence of allergy, asthma or obesity.
There have been a number of articles on this topic since the publication, in June 2012, a reference database of what constitutes a healthy microbial population. An excellent thorough examination of these data and their application was published in The New Yorker’s Annals of Science column by Michael Specter, ‘Germs are Us, Bacteria make us sick? Do they also keep us alive?’ Therein, Mr. Specter examines the impact of many modern developments that may be tweaking the population of microbiota that we harbor (especially in our gut), from the use of antibiotics, to the fiber content of the food we eat, to our obsession with cleanliness.
Amongst the scientists doing work that Mr. Specter refers to is Dr. Martin Blaser of New York University’s Langone Medical Center. Much of Dr. Blaser’s work has focused on the role of Helobacter pylori in health and disease. This organism is of special interest because a number of years ago this very organism was identified as causing gastric ulcers. In fact, I use this year after year in my own class as an example of how Koch’s Postulates were applied to pinpoint the cause of these ulcers. In those experiments it was shown that many ulcers have populations of H. pylori growing in them and that these organisms can be transplanted into the gut of a healthy patient and cause the same disease. Further, treatment that kills H. pylori results in amelioration of the ulcers.
Nevertheless, Dr. Blaser’s work does not focus on the role of H. pylori in disease, but rather on its role in maintaining the health of the organism. He, and others, have shown that ridding the body of H. pylori may result in an increased incidence of gastric reflux, asthma and obesity. This relationship is discussed in a short article in The New York Times from 2011. It may not be that H. pylori itself is responsible for all of these conditions, but perhaps other organisms that are eliminated by the same drugs that kill H. pylori contribute to these conditions.
Obviously, there is a lot going on within our bodies and a holistic view of how our actions impact a wide variety of systems may be required in order to successfully design treatments that target the ill-effects of some micro-organisms while preserving the health-promoting effects of others.
I’m definitely going to put some more work into researching this topic so I can incorporate a discussion of it in my microbiology class next semester, so don’t be surprised if you read more about this here in the future.