Who knows, nature has had the advantage of a few million years to select advantageous adaptions.

The Komodo dragon for example has a mouth infested with bacteria, bacteria that would kill you and I, they follow their prey until they pass out through infection and then eat them. The komodo is also studied for the same reason as the alligator.

Komodo dragons also possess http://en.wikipedia.org/wiki/Virulent - virulent http://en.wikipedia.org/wiki/Bacteria - bacteria in their saliva, of which more than 28 http://en.wikipedia.org/wiki/Gram-negative - Gram-negative and 29 http://en.wikipedia.org/wiki/Gram-positive - Gram-positive strains have been isolated. ^{http://en.wikipedia.org/wiki/Komodo_dragon#cite_note-20 - [21]} These bacteria cause http://en.wikipedia.org/wiki/Sepsis - septicemia in their victim; if an initial bite does not kill the prey animal and it escapes, it will commonly succumb within a week to the resulting http://en.wikipedia.org/wiki/Infection - infection . The deadliest bacteria in Komodo dragon saliva appears to be a very deadly strain of http://en.wikipedia.org/wiki/Pasteurella_multocida - Pasteurella multocida , from studies performed with lab mice. ^{http://en.wikipedia.org/wiki/Komodo_dragon#cite_note-21 - [22]} Because the Komodo dragon appears immune to its own microbes, much research has been done searching for the antibacterial molecule in the hopes of human medicinal use. ^{http://en.wikipedia.org/wiki/Komodo_dragon#cite_note-nwf-22 - [23]}