The appearance of multiresistant
of pathogenic parasitesin hospitals,for
, of multiresistant tuberculosis
bacteria, be explained by the
theory of evolution.

As any environment, TB bacteria
hospitals undergo changes in
genetic material. In the
environment however they suffer
exposition to antibiotics.
Many them die by the
action but carriers of that
provide resistance to antibiotics
proliferate freely. These
microorganisms when submitted to
antibiotics again undergo natural
and those which became
to these other drugs
preserved and proliferate. Thus
of multiresistant (nontreatable) mutant
emerge in hospitals.

The of antibiotics is a that
promotes natural selection the
emergence of multiresistant .
This is the reason hospitals often
have committees control the use of
.