Adaptations

The bacteria is able to adapt and hide inside the host cells cytoplasm and this causes the host’s immune system to be unaware of the bacteria. It is also able to adapt to extremely cold conditions and is able to survive and multiply in those situations. Many bacteria are not able to adapt to cold conditions are do not survive. It also has made an adaption for escaping the immune system’s macrophages. Where is secretes an enzyme that allows it to surpass the macrophages and go into the cell’s cytoplasm.

Another important adaption is the ability to create endospores. Endospores are not like regular reproductive spores, instead they are dormant reproductive cells. They are created when the listeria isn't able to obtain enough nutrients or is in unfavourable conditions. Inside the endospore is a core of DNA and it is able to survive long amounts of time without nutrients. Eventually, when the conditions are favourable, the spore is able to germinate and go back to being a functioning bacteria.

An example of an endospore. (Note that this is an endospore of  Carboxydothermus hydrogenoformans)
From http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.0010065