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Hello, everyone.
Welcome to this short talk,
where we will be discussing
Vibrio cholerae.
We will think about the symptoms
that this organism
is associated with
and also the virulence
factors that
make this organism a
successful pathogen.
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When we think about
Vibrio species,
Vibrio cholerae is probably
the one that everybody
has heard of.
But we also need to remember
other species as well,
such as parahaemolyticus
and also Vibrio vulnificus.
Now all of these have a
similar thing in common,
and they are all associated
with the consumption of seafood
or raw or undercooked oysters.
When we think about Vibrio
species, there are 34 species,
but only 11 are associated
with human infections.
They are gram-negative,
and they are
facultatively anaerobic,
which means they can survive in
both the presence or
absence of oxygen.
When we think about Vibrio
cholerae, there are 206 types,
and O1 and O139 are
the most common,
and they are associated
with epidemics.
We will talk about
that in a second.
Vibrio cholerae will grow
on quite simple media,
so that makes it very easy to
isolate within the laboratory.
However, we will
use selective agar
to isolate this organism.
A good example of
this type of agar is
thiosulfate-citrate-bile
salts-sucrose media,
often referred to as TCBS.
We will use this because
the ingredients will
inhibit the growth of
all other normal
flora within the gut,
and it will also help to
differentiate Vibrio cholerae.
When we think about
Vibrio cholerae,
it will grow in a nice
temperature range.
So we can isolate
Vibrio cholerae within
the temperature range
of 18-37 degrees.
It grows in the
absence of salts.
This is one of the
reasons why we can use
this media to
differentiate between
Vibrio cholerae and
other types of Vibrio,
because Vibrio cholerae will
grow in the absence of salts,
whereas other types will
require the salt to grow.
Now, we've known
about Vibrio cholerae
for a long time, 2000 years ago.
Koch called it a Kommabacillus.
The reason why he
gave it this name
was purely because it
looks like a comma.
It has a bendy shape.
Now we can differentiate between
different types of
Vibrio cholerae,
and we can use the
O and H antigens
to be able to type
the Vibrio cholerae.
We have a range of O antigens
and a common H antigen.
When we think about some of
the other organisms that
we've talked about in this
series of recordings,
it's very similar to those.
