The Secret World Inside You

Our understanding of the natural world and, crucially, how we get that understanding, is changing rapidly.

A perfect example is the current exhibition at the American Museum of Natural History, in New York, called The Secret World Inside You, which runs until August 14 this year.

What’s on display there is you and me; specifically, our microbiome – that vast array of microbes living in and upon us that outnumber our “human” cells, collectively weighs about three pounds, and, we are learning, greatly affects our health in ways that, until recently, we had no idea about. For example, our microbiome – “good” bacteria, in this case – play important roles in digestion and nutrition, obesity, mood, and immune function, among other things.

Rob DeSalle, Research Scientist in Residence at the AMNH, believes this change in our way of looking at microbes will change the way we think about ourselves and our health. It will shift medicine away from an attitude of “let’s just kill these things” to understanding how these beneficial microbes interact with us.

One example of the beneficial role played by of our microbes — and utterly counterintuitive — is the research showing that antibiotic use actually increases our risk for a future infection. That’s because antibiotics kill both good and bad bacteria. Since good bacteria help fight infection, the less we have — they’re killed by the antibiotic — the less able we are to fight off germs we encounter. The same reasoning holds for antibiotic use and an increased risk for clostridium difficile infection, a pernicious diarrhea which kills about 29,000 people within 30 days of diagnosis, each year in the United States.

However, it is one thing to know something, but it is often quite another thing to be persuaded by it and to act on it. Stanford University biophysicist Manu Prakash, in a recent interview with The New Yorker, explains how seeing is believing: “It’s not good enough to read about [the microbiome] … You have to experience it …Unless you get people curious about the small-scale world, it’s very hard to change mind-sets about diseases [and] … There’s a very deep connection between science education and global health.” To let everyone see this microworld in action, Prakash has developed a bookmark-size largely paper microscope, available to everyone this summer for the mere cost of a dollar (see preceding link).

And therein lies the value of The Secret World Inside You exhibit at the AMNH — it makes the invisible world real and meaningful. It has done so, commendably, by coming up with entertaining teaching games, quizzes, life-size animation and compelling visual effects, attractive to people of all ages (as is the website itself).

Here’s one way to gauge its effectiveness: How would you get your child to develop the habit of washing their hands so as to prevent the colonization and spread of disease-causing germs; MRSA, say? You could try a rational discussion backed up with data from the Centers for Disease Control that says it kills over 11,000 people a year in the US. Or you could have your child walk around and inspect a colorful and compelling life-size model of MRSA being attacked by a macrophage, and let that lead to a discussion about the microbial world and your health. Which do you think would do the trick? Which method of persuasion would stick with your child and perhaps even inspire him or her to become interested in the world of science and disease?

At the AMNH: An immune cell (yellow) on the attack against a swarm of disease-causing Staphylococcus bacteria (red).

At the AMNH: An immune cell (yellow) on the attack against a swarm of disease-causing Staphylococcus bacteria (red).

Getting High on Antibiotics

Direct from the department of the unexpected:

Scientists have discovered an unrecognized cause of “delirium or alterations of cognition or consciousness” in hospital patients: Antibiotics — in any one of 54 different antibiotics, including penicillin, covering 12 different drug classes. The effects often “closely resemble drug-induced psychotic syndromes caused by … [such things as] cocaine [and] amphetamines,” says Shamik Bhattacharyya, MD, from the Harvard Medical School, and lead author of the study.

How prevalent is the effect? We’re not sure. The Harvard study was a literature review that identified 391 cases from 1946 through 2013 involving patients experiencing delirium. While that number appears low we have to remember that, until now, when patients on antibiotics became delirious, antibiotics were simply never considered as a possible cause.

DeliriumAnother study, for example, has reported the number to be as high as 15%; however, that refers to a skewed patient population: critically ill patients with chronic kidney disease.

Dr. Bhattacharyya says the takeaway from his study should be this: “There are instances when antibiotics are overlooked as a potential treatable cause of delirium. [And so] the primary message … is that when patients become confused when suffering from infections, antibiotics should be included in the list of many potential causes.”

The Harvard study stands for something else too: it’s yet another example of a growing list of ill effects of antibiotics.

Barbara Warner, MD, professor of pediatrics at the St. Louis Children’s Hospital, puts it this way: “The conventional wisdom has been antibiotics can’t hurt and they might help. But our new study demonstrates that wide-scale use of antibiotics in this population does not come without cost,” says. The population Warner is talking about is preterm infants. Because they’re more prone to infection they’re routinely given antibiotics whether they’re showing signs of infection or not. But her new study found that by doing so (1) you increased resistance not just to the prescribed antibiotic but to other antibiotics as well, and (2) the routine administration of antibiotics killed “good” bacteria in the infants’ GI tract; bacteria that are needed to play vital roles in infant nutrition, bone development, and immune function.

That we need our gut bacteria for healthy immune function accounts for perhaps the most surprising ill effect from antibiotic use: an increased risk for infection. That’s the conclusion of infectious disease specialist Martin Blaser, MD, of the NYU School of Medicine, and Director of the Human Microbiome Program. His reasoning is similar to Warner’s: Good bacteria operate in conjunction with your immune system to protect you from disease. So if you knock them out with an antibiotic and are then exposed to a disease-causing germ, your chances of that germ making you sick go up – way up.

Notice that all of these ill effects occur even when the patient needs an antibiotic to treat a threatening infection. So in those cases you simply have to take the risk of delirium, and so on. What’s truly unfortunate, however, is something else entirely: that in 30 – 50 per cent of the cases where antibiotics are prescribed in hospitals, they are either unnecessary or inappropriate, according to the US Centers for Disease Control and Prevention.

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