• Question: How could the evolution or resistant bacteria and diseases affect how we treat things in the future? And how could it affect medicine?

    Asked by Hatty to Cristiane, Nicki, Nikolai, Richard, Samuel on 10 Mar 2015.
    • Photo: Samuel Ellis

      Samuel Ellis answered on 10 Mar 2015:

      Antibiotics is a huge issue at the moment, in fact it is probably THE biggest problem for medicine in the future in my opinion. Bacteria are really good at adapting to threats and conditions because of how quickly they replicate, so they evolve much faster than complex organisms. Resistance also spreads quickly because bacteria can share genes with others, so if one strain has a way of surviving an antibiotic, it can end up giving that to other more dangerous bacteria.

      The big issue is that we could run out of effective antibiotics. We really rely on them at the moment, as not only do we use them to treat diseases, but they are also used during things like surgery to stop you catching infections in the hospital. Without them working, infectious diseases could start becoming more deadly again, and a lot of medical procedures would become more risky.

      Although we discovered lots of antibiotics orginally, drug companies eventually stopped looking for them because they weren’t as profitable as things like cancer drugs. Now that resistance is a big problem, we have to race to find more, but it takes many years to develop new drugs.

      Scientists are working on this though. One way to slow the rise of resistance is to limit unnecessary antibiotic use. For example, in some countries they use antibiotics in farming to make animals grow faster, but this gives bacteria lots of chances to find resistance mechanisms. Antibiotics should also be prescribed less by doctors, eg there is no point in giving them if the patient probably has a virus and not a bacterial infection!

      Most antibiotics are found in nature, so scientists are now looking in unusual places to try and find new compounds to test. At my university there is a group studying natural antibiotics found on leafcutter ants, who use them to protect the fungus they grow for food! They have a webcam watching the ant colony you can check out (although the lights are sometimes off to simulate night time)
      https://www.uea.ac.uk/leafcutter-ants/antcam

    • Photo: Nikolai Adamski

      Nikolai Adamski answered on 10 Mar 2015:

      This is a very good question.
      When the first antibiotic (penicillin) was discovered (by accident!) we thought that we will never suffer from bacterial infections again. The problem comes from using a single antibiotic in too large quantities.
      You have to think on a population scale for this problem. Bacteria evolve quite quickly (i.e. their genes acquire new mutations and functions) because their generation time (the time it takes them to go from one generation to the next) is very short: Less than a day is enough for a new generation of bacteria to arise (Sam knows this better than me).
      In a bacterial population every now and then a bacteria will come along that is resistant to an antibiotic. If all the other bacteria in this population are killed off with an antibiotic, the resistant bacteria has a lot of space and food available, so it will multiply and form a new population. If you continue to apply antibiotics, you force the bacteria to keep the genetic changes that make them resistant. As soon as you turn off the antibiotic and introduce “wild bacteria” the resistant bacterium will be at a disadvantage, as bacteria resistant to antibiotics usually grow slower, i.e. they are outcompeted for food and space by the “wild bacteria”.
      Tl:dr
      We control the evolution of bacterial populations. By using many different antibiotics and using them sparingly, we can ensure that these antibiotics will be useful for a very long time.

Comments