A brief history of antibiotic resistance

In the days before antibiotics were widely available and widely used, people knew the dangers of infection. Even minor injuries like cuts and scrapes were taken far more seriously; just ask your grandparents. That's because an ounce of prevention is worth a pound of cure — all the more so when there isn't any cure.

Fast-forward to today. People tend not to view cuts and scrapes as being potentially serious medical conditions. Prevention seems less important, because we have a pound of cure — pounds and pounds and pounds, in fact. In 2007, people in the United States used millions of pounds of antibiotics. Therein lies the problem. With each passing year, antibiotics become less effective as bacterial populations evolve to be resistant to them.

Although recent news stories warning people about antibiotic-resistant strains of bacteria may lead you to believe that the phenomenon is relatively recent, it's actually as old as the use of antibiotics. Penicillin, the first widely used antibiotic, dates to the end of World War II. Within four years after its introduction, scientists observed resistant bacteria, and the incidence of resistance has increased steadily to the present day.

You'd think that having identified the fact that bacteria began to evolve almost immediately in response to penicillin would have encouraged people to be a bit more careful about the use of antibiotics. But we weren't, partly because it's hard to not use a medication that's so effective (many people considered penicillin to be a miracle drug) and partly because at the time, new antibiotic compounds were being discovered regularly. When one compound was no longer effective, doctors simply switched to a different compound. The scenario is very different today.

In recent years, bacteria have been gaining on us: The rate at which researchers have discovered new medically useful antibiotics has slowed, but the steady march of the evolution of resistance continues unchecked.

Antibacterials, antifungals, antivirals, and you

Most of the antimicrobial compounds at humans' disposal are compounds that are active against bacteria rather than against other microorganisms, such as fungi and viruses. Why? Because developing compounds that are active against viruses and fungi is far harder. To be medically useful, a compound has to be able to stop the invading microorganisms without hurting the person taking the compound.

At the biochemical level, bacteria are quite different from people, making it possible to target specific details of the bacterial physiology without overly affecting human physiology. The same isn't true of viruses and fungi:

^ Viruses replicate primarily by harnessing human cellular machinery. For that reason, harming the virus without harming ourselves is very difficult.

^ Fungi are quite a bit more similar to humans at the biochemical level than we might like to imagine; therefore, the substances that hurt fungi also hurt us (which is why it's so hard to cure a fungal infection like athlete's foot). Although chemicals are available that can harm the fungus pretty efficiently, the same chemicals tend to harm us, too.

This isn't to say that antibacterial compounds are without side effects. Many compounds do have side effects, which can be severe, but the medical risks of these side effects are balanced against the obvious benefits of curing the infection.

Again, the evolution of resistance isn't new. In every case, scientists have noted the existence of antibiotic-resistant bacteria shortly after the antibiotic was introduced.

Today, we humans now find ourselves facing bacteria that are resistant to many — and, in some cases, all — available antibiotics. Examples include staph, tuberculosis, syphilis, and gonorrhea. The most frightening thing we can observe from this information is that in the end, all of our antibacterial compounds end up being defeated.

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