The problem needn’t be hopeless, but it does need to be addressed. At the current rate of spread, antimicrobial resistance is forecast to lead to ten million preventable deaths a year—that’s more people than die of cancer now—within thirty years, at a cost of perhaps $100 trillion in today’s money.
What nearly everyone agrees is that we need a more targeted approach. One interesting possibility would be to disrupt bacteria’s lines of communication. Bacteria never mount an attack until they have assembled sufficient numbers—what is known as a quorum—to make it worthwhile to do so. The idea would be to produce quorum-sensing drugs that wouldn’t kill all bacteria but would just keep their numbers permanently below the threshold, the quorum, that triggers an attack.
Another possibility is to enlist bacteriophages, a kind of virus, to hunt down and kill harmful bacteria for us. Bacteriophages—often shortened to just phages—are not well known to must of us, but they are the most abundant bioparticles on Earth. Virtually every surface on the planet, including us, is covered in them. They do one thing supremely well: each one targets a particular bacterium. That means clinicians would have to identify the offending pathogen and select the right phage to kill it, a more costly and time-consuming process, but it would make it much harder for bacteria to evolve resistance.
What is certain is that something must be done. “We tend to refer to the antibiotics crisis as a looming one,” Kinch says, “but it is not that at all. It’s a current crisis. As my son showed, these problems are with us now—and it is going to get much worse.”
Or as a doctor put it to me, “We are looking at a possibility where we can’t do hip replacements or other routine procedures because the risk of infection is too high.”
The day when people die once again from the scratch of a rose thorn may not be far away.
*1 According to Dr. Anna Machin of Oxford University, something you are doing when you are kissing another person is sampling his or her histocompatibility genes, which are involved in immune response. Though it may not be the matter uppermost on your mind at that moment, you are essentially testing whether the other person would make a good mate from an immunological perspective.
*2 For the record: GTGCCAGCAGCCGCGGTAATTCAGCTCCAATAGCGTATATTAAAGTTGCTGCAGTTAAAAAG.
*3 Koch’s discoveries are of course extremely well known, and he is justly celebrated for them. What is often overlooked, however, is what a difference small, incidental contributions can make to scientific progress, and nowhere was that better illustrated than in Koch’s own productive lab. Culturing lots and lots of different bacterial samples took up a great deal of lab space and raised the constant risk of cross-contamination. But luckily Koch had a lab assistant named Julius Richard Petri who devised the shallow dish with a protective lid that bears his name. Petri dishes took up very little space, provided a sterile and uniform environment, and effectively eliminated the risk of cross-contamination. But there was still a need for a growing medium. Various gelatins were tried, but all proved unsatisfactory. Then Fanny Hesse, the American-born wife of another junior researcher, suggested that they try agar. Fanny had learned from her grandmother to use agar to make jellies because it didn’t melt in the heat of an American summer. Agar worked perfectly for lab purposes, too. Without these two developments, Koch might have taken years longer, or possibly never succeeded, in making his breakthroughs.
4 THE BRAIN
The brain is wider than the sky,
For, put them side by side,
The one the other will include
With ease, and you beside.
—EMILY DICKINSON
THE MOST EXTRAORDINARY thing in the universe is inside your head. You could travel through every inch of outer space and very possibly nowhere find anything as marvelous and complex and high functioning as the three pounds of spongy mass between your ears.
For an object of pure wonder, the human brain is extraordinarily unprepossessing. It is, for one thing, 75 to 80 percent water, with the rest split mostly between fat and protein. Pretty amazing that three such mundane substances can come together in a way that allows us thought and memory and vision and aesthetic appreciation and all the rest. If you were to lift your brain out of your skull, you would almost certainly be surprised at how soft it is. The consistency of the brain has been variously likened to tofu, soft butter, or a slightly overcooked Jell-O pudding.
The great paradox of the brain is that everything you know about the world is provided to you by an organ that has itself never seen that world. The brain exists in silence and darkness, like a dungeoned prisoner. It has no pain receptors, literally no feelings. It has never felt warm sunshine or a soft breeze. To your brain, the world is just a stream of electrical pulses, like taps of Morse code. And out of this bare and neutral information it creates for you—quite literally creates—a vibrant, three-dimensional, sensually engaging universe. Your brain is you. Everything else is just plumbing and scaffolding.
Just sitting quietly, doing nothing at all, your brain churns through more information in thirty seconds than the Hubble Space Telescope has processed in thirty years. A morsel of cortex one cubic millimeter in size—about the size of a grain of sand—could hold two thousand terabytes of information, enough to store all the movies ever made, trailers included, or about 1.2 billion copies of this book. Altogether, the human brain is estimated to hold something on the order of two hundred exabytes of information, roughly equal to “the entire digital content of today’s world,” according to Nature Neuroscience.*1 If that is not the most extraordinary thing in the universe, then we certainly have some wonders yet to find.
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The brain is often depicted as a hungry organ. It makes up just 2 percent of our body weight but uses 20 percent of our energy. In newborn infants, it’s no less than 65 percent. That’s partly why babies sleep all the time—their growing brains exhaust them—and have a lot of body fat, to use as an energy reserve when needed. Your muscles actually use even more of your energy, about a quarter, but you have a lot of muscle; per unit of matter, the brain is by far the most expensive of our organs. But it is also marvelously efficient. Your brain requires only about four hundred calories of energy a day—about the same as you get in a blueberry muffin. Try running your laptop for twenty-four hours on a muffin and see how far you get.
Unlike other parts of the body, the brain burns its four hundred calories at a steady rate no matter what you are doing. Hard thinking doesn’t help you slim. In fact, it doesn’t seem to confer any benefit at all. An academic at the University of California at Irvine named Richard Haier used positron emission tomography scanners to find that the hardest-working brains are usually the least productive. The most efficient brains, he found, were those that could solve a task quickly and then go into a kind of standby mode.