Pope Francis’s recent encyclical Laudato si’ calls on us all to conserve our natural resources for the common good. But what exactly are our natural resources? One obviously thinks of energy, water, air, and other environmental basics. But I believe the list should include something that may surprise many people: antibiotics. After all, many antibiotics come directly from nature; streptomycin, cephalosporins, and tetracyclines, for example, are compounds recovered from soil-dwelling microorganisms that effectively kill other microorganisms. And, of course, antibiotics serve our common good.

The medicines listed above were discovered during last century’s golden age of antibiotics, an era when new antibiotics were developed in such abundance that most people believed, as U.S. Surgeon General William Stewart put it in 1967, that “the time has come to close the book on infectious diseases.” Stewart’s vision of the future was triumphant: “We have basically wiped out infection in the United States.”

Obviously, fifty years later, we have not wiped out infection—in the United States or anywhere else. In fact, we face a potentially explosive crisis of infection. Alexander Fleming, the discoverer of penicillin, warned in his 1945 Nobel Peace Prize acceptance speech that indiscriminate use of penicillin might spur the development of penicillin-resistant bacteria. His prediction has proved accurate, and not merely for penicillin. For every antibiotic now used in human medicine, at least one fully resistant bacterial strain has been identified somewhere in the world. Indeed many bacterial species have become resistant to multiple antibiotics, making some infections virtually untreatable. These multidrug-resistant bacteria, christened “superbugs” by the popular media, have opened the door to what scientists are calling “the post-antibiotic era,” threatening a return to the time when a diagnosis of pneumonia, sepsis, or meningitis was often a death sentence. Reversing the rosy predictions of fifty years ago, Dr. Margaret Chan, director-general of the World Health Organization, recently warned that the post-antibiotic era will be “the end of modern medicine as we know it.”

So what happened? The simple answer is evolution. Not the evolutionary process, cited in Laudato si’, that took millennia to unfold and gave us fish, birds, mammals, and humans, but rather the short-term evolutionary process that occurs in microbial species over mere days or weeks. This process reflects the ability of all microorganisms to enhance their survival either by mutating their genetic code or acquiring additional genetic information from other microorganisms. Bacteria, in particular, are highly promiscuous microorganisms that readily share genetic information with one another, even across the barriers of divergent species. When antibiotics are used to treat an infection, resistant bacteria can survive and flourish and rapidly become the predominant bacterial population. As the infection spreads throughout a patient’s body, the resistant organisms spread into the environment and often find their way to other patients. The infected patient may board an airplane, visit Disneyland, attend the Hajj, or simply head to a subway station, transferring the resistant bacteria to a hundred other people along the way. Meanwhile, the genetic information that enables the bacteria to be resistant to antibiotics can be transmitted to other bacterial species. Such is the story of the global spread of multidrug-resistant bacterial infections.

Containing this spread will not be easy. Although the antibiotic pipeline of new drugs for use against human infectious diseases is not dry, neither is it overflowing. Antibiotics no longer contribute as much to the bottom line of major pharmaceutical companies as they once did. It may take fifteen to twenty years for a new compound to be approved for use, and profits are often not realized until well after that. Furthermore, less than 3 percent of compounds make it successfully from early development to the market. Given the choice between developing an antibiotic that may be used for only one to two weeks and developing a drug for a chronic disease, like diabetes, which is taken for a lifetime, pharmaceutical companies typically choose the latter. For these reasons, companies around the globe are putting less effort into developing truly innovative new antibiotics; many have stopped developing antibiotics completely. To date, government incentives intended to boost development have seen little success.

The stark reality, then, is that instead of waiting and hoping for a new miracle antibiotic, we need to make much better use of the antibiotics we currently have. To this end, three points need to be understood: (1) antibiotics are a limited resource; (2) overuse creates resistant organisms and decreases the antibiotic’s overall effectiveness; and (3) every person has a role to play in avoiding the onset of the post-antibiotic era.     

Scientists acknowledge that antibiotics are required to combat serious infection in animals, plants, and humans. Antibiotics have revolutionized modern medicine, from fighting disease to decreasing childbirth risks to facilitating organ transplantation. But with use comes abuse. Patients diagnosed with viral infections often press their doctors for antibiotics; and since a physician’s compensation is often based at least in part on patient satisfaction scores, some physicians will provide that prescription even when it isn’t indicated. Many struggle to balance keeping individual patients happy against the societal need to preserve the effectiveness of antibiotics for the long term. 

Progress in reducing unnecessary prescriptions means educating health-care providers to understand that their oath to “do no harm” precludes prescribing antibiotics indiscriminately. To that end, government health officials have recommended the establishment of antibiotic stewardship programs in all U.S. hospitals and long-term-care facilities by the end of 2017. Such programs encourage physicians to treat infections with the right antibiotic, at the right dose, for the right duration, and to avoid giving antibiotics when they are unnecessary.

As Laudato si’ suggests, there is also a role for personal responsibility in preserving this natural resource—for patients as well as physicians. Both groups need to recognize their role in the big picture of preserving antibiotics for future use. The stakes are high. The economist Lord Jim O’Neill, in his report to the prime minister of the United Kingdom, noted that in the absence of new interventions, and given the current trajectory of infectious diseases globally, by 2050 antibiotic-resistant infections will claim 10 million lives at a cost of $20 trillion, far outstripping the number of lives and costs claimed by cancer in the same time period.

Thus, when we consider Laudato si’ and the call to conserve our natural resources and strive for a just world, placing antibiotics on the list for conservation is not a stretch. Though we cannot close the book on infectious diseases, we can reduce their incidence—while promoting human health and dignity—by providing clean water, improved sanitation, vaccination programs, and better health-care globally. When infections do occur, we need access to a supply of reliable antibiotics. Currently, our ability to meet that demand on a global basis is being taxed. It should not be. We need to do better.