Ever wondered ... about antibiotics?

 12 Jun 2016 - 11:43

Ever wondered ... about antibiotics?


By Howard Bennett

I saw a 4-year-old the other day with a bunch of crusty, red lesions on his body. ("Lesion" is the doctor word for an area that's been damaged by infection or injury.) The diagnosis was impetigo (im-pa-TIE-go), a bacterial infection usually caused by strep or staph. Although impetigo isn't serious, it needs to be treated with antibiotics.

Antibiotics are medications used to fight bacterial infections. If you've ever had a strep throat or ear infection, there's a good chance you've taken amoxicillin, one of the most widely prescribed antibiotics in the world.

Scientist Alexander Fleming discovered penicillin in 1928 when he noticed that bacteria he was studying wouldn't grow near a mold called Penicillium notatum.

Antibiotics kill bacteria in different ways. Some, such as penicillin, weaken the cell wall, causing bacteria to burst when they reproduce. Others slow down bacterial growth so your immune system has a better chance to kill them.

Nowadays, antibiotics are relatively easy to produce, but this wasn't always the case. The first patient treated with penicillin was a British policeman who developed a severe infection in 1941 after being scratched by a thorn. Lucky for him, he was in a hospital where research was being done on penicillin. Unlucky for him, the treatment didn't work.

Here's what happened: The patient was very sick but started to improve after the first dose of penicillin. Because doctors were still learning how to use penicillin, they didn't have enough on hand. They tried something cool (and gross) to overcome the problem. Penicillin is eliminated from the body by the kidneys. The doctors filtered "used" penicillin from the patient's urine and gave it back to him. This worked until they ran out of the drug five days later. The patient died.

Since penicillin was discovered, scientists have invented hundreds of antibiotics to treat a wide variety of infections. Antibiotics can be swallowed, spread on the skin or injected. The development of antibiotics was such a major advance that in 1945 Fleming and two other doctors received a famous award called the Nobel Prize.

You may have heard that bacteria are becoming resistant to antibiotics. This means antibiotics that killed bacteria in the past are no longer effective.

Antibiotics work by disrupting some aspect of bacterial function. But over time bacteria can mutate, or change. Let's say a bacterium accidentally makes an enzyme (chemical) that reduces the effectiveness of an antibiotic. This bacterium is more likely to survive and reproduce than one that is not resistant to the antibiotic. Over time, more and more bacteria will be "stronger" than the antibiotic until the drug no longer works.

Bacterial resistance comes from overusing antibiotics. In some cases, they're prescribed for viral infections, even though antibiotics don't work against viruses. Instead, they can kill "good" bacteria and allow others to thrive. That leads to resistant infections.

The best way to stop bacterial resistance is to be cautious about using antibiotics. They should not be prescribed for viral infections. Also, they may not be needed for infections that can get better without medication, such as mild ear and sinus infections.

Pay attention the next time your doctor recommends an antibiotic. Did your parents explore other options? If so, give them a high-five!

The Washington Post