In: Chemistry
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.