• Question: How hard is it to find bacteria and bugs on your skin?

    Asked by maryclevergirl to Amar, Andrea, Leah, Matt on 19 Mar 2014.
    • Photo: Matthew Lam

      Matthew Lam answered on 19 Mar 2014:


      Not very hard at all…your skin is covered in bacteria! But they’re unlikely to cause you harm as your immune system is so used to them that an infection is unlikely to happen.

    • Photo: Andrea Hanvey

      Andrea Hanvey answered on 19 Mar 2014:


      its easy your body is covered in bacteria inside and out! some times when we have antibiotics they kill the good bacteria aswell as the one making you ill, this can lead to other problems like thrush when fungi take the opportunity to grow due to reduced good bacteria!

    • Photo: Leah Fitzsimmons

      Leah Fitzsimmons answered on 19 Mar 2014:


      Like the others said, we are covered in bacteria, both inside and out. We have evolved to live with bacteria over millions of years – most of the time they don’t cause any harm and the right types in the right amounts can actually be beneficial for us! However, there are some types that can harm us, especially if they get somewhere they shouldn’t be and grow out of control so the body can’t kill them – like when a wound gets infected with bacteria that usually live outside of our bodies.

      To actually find bacteria on your skin you could try different experiments:
      – if you put your hand onto agar (a jelly that bacteria can live on) and then keep it somewhere warm then you can grow some of the bacteria from your skin. A microbiologist could tell what type of bacteria it was from how they grow on agar.
      – to find out very specifically what the bacteria was (to help decide on how to get rid of it) you could look down the microscope at some, or even better, look what DNA was in the bacteria. Because some harmful types of bacteria are very similar to their harmless cousins, sometimes we have to do lots of tests to figure out exactly which is which.

    • Photo: Amar Joshi

      Amar Joshi answered on 20 Mar 2014:


      Hi Mary, the others are right bacteria are everywhere. You could take a cotton bud, smear it over a patch of skin and grow loads of them in a petri dish!!

      But you might also find literal bugs – small insects and mites on your skin or in your hair. There is a type of mite that lives quite happily in hail follicles (the bit of the hair root in your skin). We are totally covered in hair follicles even though the hair itself might be very fine and fair. It is estimated that 1 in 3 children and half of adults have these mites!! But don’t worry, they are usually harmless and less than a millimetre in size.

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