how bacteria can natural select to become resistant to antibiotics in decades but not resistant to heat (cooking), ethanol (fermentation), and/or salt after tens of thousands of years of contact w these pressures.

Question

Why is cooking still an effective way of eliminating human pathogens or fermentation or salting? These methods do not eliminate all traces of the bacteria so what is keeping a random mutation from happening that allows, say, e. Coli in beef to become resistant to heat up to 60c or Listeria to resist salt concentrations to the same levels as bacteria which are not infectious and potential beneficial to us that can tolerate?

What is it about antibiotics that makes them so susceptible to creating these random mutations that antibiotics become near obsolete in decades?

In: 24

Answer 1

Antibiotics work on bacteria’s existing machinery to prevent them from establishing an infection by inhibiting replication, mobility, release of toxins, etc. Resistance occurs when the genome of the bacteria modifies itself to tweak it’s existing machinery so the antibiotic’s strategy is no longer effective. Resistance to environmental factors like heat and salinity require a series of genetic mutations across generations of bacterial strains i.e. evolution whereby only the bacteria possessing mutations/genes most compatible with the harsh environment will survive. These exist and are called extremophiles. They only exist in biologically extreme environments, however. E coli lives in GI tracts and in the soil, they have no need for becoming resistant to high temps or salinity since the majority of E coli populations will never be exposed to such factors.

In theory, you could take a strain of E coli and gradually expose them to high salinity, select the cells that survive and allow them to replicate while incrementally increasing the salinity to create a high-salinity tolerant strain of E coli.