Science Questions

Will bacteria become resistant to soap or bleach?

If bacteria are constantly evolving and developing resistance to things like antibiotics, why don't they become resistant to soap, ethanol or bleach? Dan

This is because antibiotics work in a very different way to bleach.  Bleach will kill pretty much everything, but antibiotics work in a much more subtle way.  Most antibiotics work by targeting specific proteins, such as ones in the cell wall, or those that help make other proteins.  A population of bacteria will have variation in genes between one bug and the next and so some will survive.  The bacteria that do survive are the ones with variations in their genes which let them cope against the drugs, and so these go on to divide and replace the ones killed by the antibiotics.  Bleach is so utterly destructive that virtually nothing survives, so no 'resistance' genes get spread throughout the population.

Most of the drugs we have are derived from a natural source, so bacteria have been locked in this 'arms race' for a very long time.  Long before we started using these chemicals to fight off infection.

September 2007