Some Interesting Facts from "Missing Microbes"

On the Microbiome

  • The microbes on Earth would outnumber all the other flora and fauna on Earth--and outweigh them as well.
  • Your body is composed of 10 trillion human cells, but is host to around 100 trillion bacterial cells.  Your body bacteria cells outnumber your own human cells ten to one.  
  • All the bacteria on and in your body weigh about three pounds, roughly equivalent to your brain.  One millionth (about a thousandth of a quart) of colonic contents (and each person has several thousand milliliters) contain many more bacteria than there are people on Earth.
  • Up to 15 percent of the calories present in your food are extracted by guest bacteria in your colon and used to feed you.
  • 99.9 percent of the unique genes in your body are bacterial, and only about 0.1% are human.
  • By age three, each of us has acquired our own unique foundation of microbes.  The makeup of this microbiota is relatively permanent throughout our lives.

On Antibiotics

  • All strains of penicillin today are descendants from one moldy cantaloupe discovered in 1943.
  • By 2010, health-care providers prescribed 258 million courses of antibiotics to people in the United States, equal to 833 prescriptions for every thousand people across the country.
  • The highest prescription rate was for children under the age of two: 1,365 courses per 1,000 babies.  This means that the average American child received nearly 3 courses of antibiotics in his or her first two years of life.  They go on to receive, on average, another 8 courses over the next eight years.  
  • Every year, one in five people in the United States takes a course of azithromycin (Z-pack).
  • Even short term antibiotic treatments can lead to long term shifts in the microbes colonizing our bodies.
  • 70-80% of the antibiotics sold in the United States are used to accelerate growth rates of farm animals. In 2011, animal producers bought nearly 30 million pounds of antibiotics, the largest amount yet recorded, for their livestock.
  • In 2011 more than half the samples of ground turkey, pork chops, and ground beef collected from supermarkets for testing by the federal government were found to contain bacteria resistant to antibiotics.
  • Milk can legally have up to 100 micrograms of tetracycline per kilogram.  A 1990 report indicated that 30-90 percent of milk samples had detectable antibiotics, especially sulfa drugs and tetracycline.
  • A 2009 study of several cities in Michigan and Ohio found antibiotic-resistant bacteria and genes in all source waters, drinking water from treatment plants, and tap water.

On the Microbiome and Childbirth

  • The rate of C-sections in the United States increased from one in five births in 1996 to one in three births in 2011--a 50% increase.  
  • With vaginal births, the baby is covered with the mother’s vaginal microbes.
  • Today, babies are cleaned immediately, removing this coating of mother’s microbes, which has hundreds of useful constituents, including proteins that suppress specific dangerous bacteria.
  • Caesarian delivery is a largely unrecognized threat to the microbial handoff from other to child.
  • 40% of women are given antibiotics during childbirth.
  • All American babies receive an antibiotic immediately after birth in the form of eye drops to prevent a rare infection called gonococcal opthalmitis.

On our modern plagues

  • In 1990, 13% of Americans were obese. In 2010, it was 30%.  As of 2008, according to the World Health Organization, 1.5 billion adults are overweight, and over 200 million men and over 300 million women were obese.
  • Early life antibiotics change the development of mice through their effect on resident microbes; making them larger and fatter. Studies are showing similar effects in children.
  • Juvenile diabetes has been doubling every twenty years across the industrialized world, and is more likely to develop in babies born by C-section.
  • One in 14 people in America had asthma in 1999, but only a decade later it was one in 12.
  • Antibiotic use within the first year of life was associated with a significantly greater chance of having asthma at the age of seven.  A Canadian study showed double the risk of asthma in children who received antibiotics during the first year of life.
  • The incidence of celiac disease has skyrocketed in recent decades, more than quadrupling since 1950. People who had recently developed celiac disease were about 40% more likely to have taken antibiotics in the preceding months compared to those who didn’t.

On Overuse of Antibiotics and the Threat of a Superbug

  • Increased susceptibility to new infections is one of the hidden costs of antibiotic use.
  • Drug resistant bacteria such as C. diff and MRSA are on the rise due to overuse of antibiotics.
  • At least 250,000 people are hospitalized each year for C. diff infections they acquired there or at home.  14,000 die as a result.
  • It takes 1 million organisms of salmonella bacteria to infect mice with normal microbiomes.  After a single dose of antibiotics, it took only 10 organisms to infect them.  That is a one hundred thousand-fold difference.
  • When people take a broad-spectrum antibiotic, the kind most frequently prescribed, it may be the case that rare microbes get wiped out entirely.  As far as your body is concerned, that species is now extinct. An extinct species may be a “contingency organism” that could prevent you from a lethal pathogen.
  • Recent studies suggest that otherwise normal individuals have lost 15-40% of their microbial diversity and the genes that accompany it.