• Question: Can all bacteria be killed using antiseptics, or just some of them?

    Asked by to Bethany, Hannah, Keith, Peter, Ramya on 20 Jun 2014. This question was also asked by .
    • Photo: Hannah Tanner

      Hannah Tanner answered on 20 Jun 2014:

      An antiseptic is a disinfectant you can apply to your skin. There are several different chemicals which are used as antiseptics and in general they will kill most bacteria but not all of them.
      One particular problem is the spores which Bacillus and Clostridium bacteria can make. Bacterial spores are bacteria in survival mode. The bacterium has shut down most of its functions and grows a thick protective coating on the outside. Spores are much more resistant to heat, drying out and chemicals than the normal growing cells. The spores can survive when the environment is too difficult but as soon as the conditions are right again the spores can germinate and get growing.
      One of the most common antiseptics is 70% ethanol (alcohol). This kills normal bacteria very effectively but has no effect on spores. This is why it’s so important to wash your hands and not just use alcohol gel rubs. Spores wash off with soap and water even if it doesn’t kill them.

    • Photo: Bethany Dearlove

      Bethany Dearlove answered on 22 Jun 2014:

      As Hannah said, antiseptics are substances that you can apply to your skin to reduce the possibility of infection. There are two types: ones that can kill the bacteria, and ones that only prevent or slow down their growth enough to not be dangerous. They generally work by exploiting differences between our skin, and the bacteria – for example breaking down the bacterial cell wall. Although antiseptic resistance isn’t as common as antibiotic resistance, it still does occur, and therefore it’s still important to get the amount of antiseptic right to kill the bacteria off as intended.

    • Photo: Peter Elliott

      Peter Elliott answered on 23 Jun 2014:

      Antiseptics are indeed a good way of killing bacteria. Although as Bethany points out there is a fear of resistance developing as has occurred with many antibiotics. To combat this we use a combination of antibiotics to try and prevent further resistance and so maybe we will have to try and develop combination antiseptics to try and prevent bacteria from becoming resistant to them also.

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