The many roles of bacteria: a snapshot

Tana LoyAssociate Medical Writer



As it often happens on my drive home, I hear a snippet of something absolutely fascinating on NPR, usually on Fresh Air with Terry Gross, and when I get a chance later, I surf the Web for more information. This week was no exception. On a recent episode, Terry’s guest was Dr. Martin Blaser, the NYU Muriel G. and George W. Singer Professor of Translational Medicine, director of the Human Microbiome Program at NYU, and the former president of the Infectious Diseases Society of America. In addition to his academic positions, Dr. Blaser has appeared on television programs such as Dr. Oz and has just released a new book, Missing Microbes: How the Overuse of Antibiotics Is Fueling Our Modern Plagues. Yes, a nerdy topic to some, but bear with me—and don’t worry, this isn’t a book review!

Dr. Blaser posits that bacteria, or rather the lack thereof, are a plausible explanation for the rise of obesity, asthma, allergies, and even celiac disease, but he also points out that bacteria may have therapeutic benefits. All of his research on bacteria is fascinating, especially his study of Heliobacter pylori, a microbe that has been shown to cause stomach ulcers and even gastric cancer, but we are going to concentrate on a couple of topics he covered in the Fresh Air episode that may prompt us to make different, maybe even better, decisions about our health now: the proper development of the human microbiome and the addition of antibiotics to livestock feed.

The National Institutes of Health describes the microbiome as “the community” of microbes that exist in and on our bodies. Those horror movies in which a person becomes a host for a foreign organism are not exactly farfetched. In fact, about 70% to 90% of cells in the human body are microorganisms!

Most medical writers have a few topics about which they are passionate, and for me, maternal healthcare is a topic I love to research and talk about. I am particularly supportive of breastfeeding (as is the American Academy of Pediatrics) and of medical and surgical intervention free childbirth (as appropriate) in low-risk, full-term pregnancies. In fact, abundant microbiologic evidence suggests that vaginal deliveries and exclusive breastfeeding may be the best ways of ensuring good health for newborns. Not surprisingly, Mother Nature knows what she is doing.

Your microbiome starts at birth. Babies in the womb are essentially sterile, but it is during delivery that they begin to establish their microbiome. In a 2010 study, Dominguez-Bello et al showed that “vaginally delivered infants acquired bacterial communities resembling their own mother's vaginal microbiota, dominated byLactobacillusPrevotella, or Sneathia spp., and those delivered by C-section harbored bacterial communities similar to those found on the skin surface, dominated byStaphylococcusCorynebacterium, and Propionibacterium spp.” (Proceedings of the National Academy of Sciences.

These results have important implications for the most basic thing a newborn does—eating!

The mother’s microbiome is so smart, it actually changes during pregnancy. Her birth canal increases production of lactobacilli, bacteria that, you guessed it, break down milk. Long story short—baby is born vaginally, baby is coated with microbes (including lactobacilli), baby “inoculates” mom’s breast with the bacteria, the bacteria enter the baby’s gut when she starts to eat, and boom! The microbiome foundation has been set.

The microbiome matures and undergoes the most development during the first 2 to 3 years of life, and it quite possibly sets the stage for many aspects of your health for the rest of your life. Evidence shows that the interruption in the development of the microbiome (by, for example, fatty foods or inappropriate use of antibiotics) can affect many aspects of our health and wellness—even our waistlines. We’ll come back to that later.

Now let’s switch gears to the use of antibiotics in livestock feed. In the world of diet and nutrition, where the “eat this, not that” information is constantly changing, you may have heard that you should consume only some combination of organic, humanely raised, grass-fed, free-range, hormone- and antibiotic-free all-natural meat or poultry. I know, I know, I struggle to keep up with the newest studies, too. But here is the kicker—does the average consumer understand why he or she should choose antibiotic-free meat?

The explanation that may first come to mind is that when we consume meat from animals who have received antibiotics, it increases our resistance to antibiotics, leading to those pesky “superbugs.” That may be true, but let’s examine this from a different angle. These animals receive antibiotics not just to prevent illness linked to production conditions but also to make them grow! In fact, the antibiotics are given at subtherapeutic levels, meaning that the amount of antibiotic they receive would not likely have any effect on harmful bacteria. Dr. Blaser explains that farmers give antibiotics to livestock because they promote growth. So if farmers are using antibiotics to promote growth in livestock, are the antibiotics we take making us fatter? Although they may not be the primary contributor to an increased risk of obesity, they may certainly be a factor.

Dr. Blaser’s lab conducted experiments on mice to demonstrate what effect bacteria had on obesity. In one experiment in which mice were raised on both high-calorie food and antibiotics, the results of the study were dramatic, particularly in female mice. Those mice gained about twice as much body fat as a control-group of mice that ate the same food but did not receive antibiotics. Dr. Blaser concluded that for the female mice, the antibiotic exposure was the switch that converted more of those extra calories to fat, but the males grew more in terms of both muscle and fat. He tells theNew York Times that “the observations are consistent with the idea that the modern high-calorie diet alone is insufficient to explain the obesity epidemic and that antibiotics could be contributing.”

It is important to note that most scientists, Dr. Blaser included, believe in the use of antibiotics when appropriate. He suggests that a breakthrough in medicine will be the development of rapid-result tests that can detect the exact harmful bacteria that are causing illness. With these tests, bacteria-specific antibiotics can be prescribed. In addition, fecal transplantation is emerging as a treatment for dire infections, such as from Clostridium difficile.

So let’s look at the big picture. How can Artcraft Health help? Surely, we can’t address all of the points covered in this article, let alone all of the different ways our microbiome affects us. But wait, yes. Yes, we can, and it all starts with patient education.

Many women (and patients in general) are not offered health information that is easily understood. They trust their doctors to make the decisions about their bodies, sometimes with poor outcomes. But what if women were educated to understand the way their child enters this world can have long-term effects on their baby’s health? Would this information change their birth plans or health behaviors during pregnancy, childbirth, and even general pediatric care? For example, rather than relying on a broad-spectrum antibiotic to treat an ear infection in a 1-year-old, what if we can offer tests that would indicate a specific antibiotic for targeting the infection?

Going even further, can we campaign for more research on the effects of antibiotics in livestock feed? The US Food and Drug Association has already revised their policies on subtherapeutic antibiotics in feed. As consumers, and patients, should we seek (or better yet, be given) information from dieticians and primary care providers about the potential benefits of organic, antibiotic-free meat?

Above all, it is extremely important to empower patients and consumers to learn how their bodies have adapted to our modern lifestyle and to understand the repercussions that our choices have on all aspects of our health. Everyone has the capacity to understand any information, as long as it is clear, actionable, relevant, and engaging (CARE™). Artcraft Health understands the needs of patients, and we can deliver practical and essential health information through our CARE Principles. From prenatal care to what chicken to choose at the market, AH delivers.

To learn more about the topics covered in this post, please visit the following sites:

The Human Microbiome Project

Guardian article on gut bacteria analysis and sequencing

How microbes effect the body

Antibiotics in food animal production

Childbirth delivery method and initial microbiota

Modern use and consequences of antibiotics