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0:00
Hi. My name is Brett Finlay.
I'm the series editor
for this section of
the Henry Stewart Talks entitled
"The Molecular Basis of
Bacterial Pathogenicity".
In addition to compiling the
various invited speakers,
my job for this lecture
is to overview at
a molecular basis how
bacteria cause disease.
This is obviously a
very large subject.
In this lecture, I will just
highlight some of the
areas that you can expect
to find in some of
the more specialized
talks in this series.
0:32
As we know infectious diseases
continues to plague the world.
At least a third of all
deaths worldwide are due to
some infectious agent and these
are not confined to the
developing countries.
In developed countries,
we see one in
five deaths due to
an infectious agent.
Compiling this are the
newly emerging organisms,
the re-emerging diseases,
and the potential of
bioterrorism-type agents.
Thus infectious
diseases including
bacterial diseases
continue to plague
this world and we
continue to strive to
ways to combat these agents.
1:11
It is thought that at
least 100 bacteria have
the potential to cause
specific diseases in humans.
On this slide is a
long list of some of
the bacterial cause diseases
that we encounter as humans.
We will not go through
these individual diseases
but I illustrate
the complexity and diversity
of diseases caused by
bacterial pathogens.
1:37
The question is how do
bacteria actually cause
these diseases and what kind of
molecular tools do they use
to achieve these effects?
If one is to consider how an
infection actually occurs,
there are several
steps that a pathogen
goes through before we
ultimately see disease.
At each of these steps,
bacterial pathogens have
evolved specific factors called
virulence factors
that allow them
to proceed through particular
steps of infection.
The first steps are
the initiation of the
exposure to the pathogen.
That is you may swallow
an organism or it may
contact your skin or
wherever on the body.
To be successful a pathogen
has to recognize that site
and ideally set up a
colonization at that point.
This can be specific adherents
say to mucosal surface
or it can even go on to
dig deeper in the tissues,
that is invade and penetrate
through the epithelium
and then going on to spread
to further sites in the body.
A key aspect of
micropathogenesis is
the ability of the pathogen
to grow and increase in numbers.
The pathogen enters as one
and does not replicate.
You can imagine that does
not cause further disease.
There are several side effects
that this pathogen causes in
the host and this is often
represented by the actual
presentation of disease.
This is often due to
various detrimental effects to
the host such as tissue damage,
inflammation, et cetera
and this is what
we see as bacterial disease.
