Antibiotics: behind the scenes,  they enable much of modern medicine. We use them to cure infectious diseases, but also to safely facilitate everything  from surgery to chemotherapy to organ transplants. Without antibiotics, even routine medical procedures  can lead to life-threatening infections. And we’re at risk of losing them. Antibiotics are chemicals  that prevent the growth of bacteria. Unfortunately, some bacteria  have become resistant to all currently available antibiotics. At the same time,  we’ve stopped discovering new ones. Still, there’s hope that we can get ahead  of the problem. But first, how did we  get into this situation? The first widely used antibiotic  was penicillin, discovered in 1928 by Alexander Fleming. In his 1945 Nobel Prize  acceptance speech, Fleming warned that bacterial resistance  had the potential to ruin the miracle of antibiotics. He was right: in the 1940s and 50s, resistant bacteria  already began to appear. From then until the 1980s, pharmaceutical companies  countered the problem of resistance by discovering many new antibiotics. At first this was a highly successful—  and highly profitable— enterprise. Over time, a couple things changed. Newly discovered antibiotics  were often only effective for a narrow spectrum of infections, whereas the first ones  had been broadly applicable. This isn’t a problem in itself, but it does mean that fewer doses  of these drugs could be sold— making them less profitable. In the early days,  antibiotics were heavily overprescribed, including for viral infections  they had no effect on. Scrutiny around prescriptions increased,  which is good, but also lowered sales. At the same time,  companies began to develop more drugs that are taken over a patient’s lifetime, like blood pressure  and cholesterol medications, and later anti-depressants  and anti-anxiety medications. Because they are taken indefinitely,  these drugs more profitable. By the mid-1980s, no new chemical classes  of antibiotics were discovered. But bacteria continued to acquire  resistance and pass it along by sharing genetic information  between individual bacteria and even across species. Now bacteria that are resistant  to many antibiotics are common, and increasingly some strains  are resistant to all our current drugs. So, what can we do about this? We need to control the use  of existing antibiotics, create new ones, combat resistance to new  and existing drugs, and find new ways to fight  bacterial infections. The largest consumer  of antibiotics is agriculture, which uses antibiotics not only  to treat infections but to promote the growth of food animals. Using large volumes of antibiotics increases the bacteria’s exposure  to the antibiotics and therefore their opportunity  to develop resistance. Many bacteria that are common in animals,  like salmonella, can also infect humans, and drug-resistant versions can pass  to us through the food chain and spread through international trade  and travel networks. In terms of finding new antibiotics, nature offers the most promising  new compounds. Organisms like other microbes and fungi  have evolved over millions of years to live in competitive environments— meaning they often contain  antibiotic compounds to give them a survival advantage  over certain bacteria. We can also package antibiotics  with molecules that inhibit resistance. One way bacteria develop resistance  is through proteins of their own that degrade the drug. By packaging the antibiotic with molecules that block the degraders, the antibiotic can do its job. Phages, viruses that attack bacteria  but don’t affect humans, are one promising new avenue  to combat bacterial infections. Developing vaccines for common infections, meanwhile, can help prevent disease  in the first place. The biggest challenge to all  these approaches is funding, which is woefully inadequate  across the globe. Antibiotics are so unprofitable  that many large pharmaceutical companies have stopped trying to develop them. Meanwhile, smaller companies  that successfully bring new antibiotics to market often still go bankrupt,  like the American start up Achaogen. New therapeutic techniques  like phages and vaccines face the same fundamental problem  as traditional antibiotics: if they’re working well,  they’re used just once, which makes it difficult to make money. And to successfully counteract resistance  in the long term, we’ll need to use  new antibiotics sparingly— lowering the profits  for their creators even further. One possible solution is to shift profits  away from the volume of antibiotics sold. For example, the United Kingdom  is testing a model where healthcare providers  purchase antibiotic subscriptions. While governments are looking for ways  to incentivize antibiotic development, these programs are still  in the early stages. Countries around the world  will need to do much more— but with enough investment  in antibiotic development and controlled use of our current drugs, we can still get ahead of resistance.