Hi, and welcome to our video on Beta-lactam
antibiotics and vancomycin.
So we want to start right out letting
you know that cephalosporins,
carbapenems, and monobactams
are beta-lactam antibiotics.
Vancomycin is a separate 1 that I wanted to
group together with these three
So let's open up with a question.
Why are they called Beta-Lactam Antibiotics?
So, pause and just write the answer
in the margin of your notes.
Now, if you've seen our other
video on penicillins,
you know, they're called
because all these antibiotics
share a common chemical structure --
a beta-lactam ring.
And there's 4 major subclasses
of beta-lactam antibiotics.
We talked about the penicillins
in a separate video.
But now we're going to talk about
the carbapenems, and the monobactams,
and we'll wrap up with vancomycin
a little later.
Remember, it is not a beta-lactam
but we just included it with this group.
Now, we're going to take a look at 5
generations of cephalosporins.
The first through the fifth generation.
Now, they get better with age.
I'm going to walk through each generation,
1 at a time, and they're named
first, second, third, and so on,
because that's the order
they were discovered.
So, first generations are the
Fifth generations are the
I'm going to, kind of, give you an overview
at the end, but let's take a look at these.
The first generation of cephalosporins,
they go after gram-positive bacteria.
They really don't do much for gram-negative.
Now, I want you to look at the third
column. This is where things get
really interesting with the cephalosporins.
Now, you see we have a note there. It says
it's not effective concentrations in CSF.
That stands for cerebral spinal fluid.
We put that note there because
this first generation
can't get into the central nervous system.
Remember, the cerebral spinal fluid is what
lubricates that central nervous system,
and the first generations can't
cross over to that.
So if we can't get a strong
concentration in the CSF,
the cerebral spinal fluid,
then we're going to not be able to treat an
infection in the central nervous system.
Now, second generation
gets a little bit better about gram-negative,
but look at that third column.
Right. Second generations are not able to get
an effective concentration in your CSF,
your cerebral spinal fluid,
meaning we can't use these
to treat infections
in the central nervous system.
It's also not active against
Third generation is highly effective
against gram-negative bacteria.
Okay, so first was not very good.
Second, got a little bit better, but
third is where it really starts to get good.
This is also the first generation
that can actually
cross into the cerebral spinal fluid.
So, these were the first types
that we were able to use for types of
central nervous system infections,
So these were the drugs of
choice for meningitis
that are caused by gram-negative bacilli.
So, now it's starting to become a
little clearer when I said
as the new drugs were discovered,
they got better.
They got better at dealing
and they got better at crossing into
the central nervous system.
Remember, first and second do not cross
into the central nervous system.
Third is the one that's, so far, the best
against gram-negative bacteria,
and it does cross into the CNS.
Now, the fourth generation
we use for healthcare
and hospital-associated pneumonias.
That means they came in for our care,
and we gave them a pneumonia.
So the fourth generation has an
in the cerebral spinal fluid too;
cool. That means we can also use it
get across that barrier into the cerebral
spinal fluid. But remember,
the third generation is still our
first choice for meningitis.
So, from the third generation on down,
these antibiotics can actually cross
into the central nervous system.
Remember, your CNS is protected
by that blood-brain barrier.
Got those super tight junctions
so that the bugs, or the drugs actually have
to go through the cell to get there.
Only the third and fourth generation
can actually accomplish that.
The fifth generation is the
coolest of them all.
It is the only 1 of the generations
that can be used to treat MRSA.
Now, we've talked about MRSA
before, but it stands for
methicillin-resistant Staphylococcus aureus.
So that's a staph infection that we used
to be able to treat with methicillin,
but now it is resistant.
So that the fifth generation can do
that is over-the-top cool.
Now, it can also get into your cerebral
spinal fluid, but remember,
third generation is our favorite,
right now, for meningitis.
What's cool about the fifth generation
is that it can be used to treat MRSA,
which is a resilient and kind of nasty bug.
So, when you're thinking about the different
generations of the cephalosporin,
they just simply get better with age.
In the third generation, again, we can
cross over to cerebral spinal fluid,
fourth, and fifth. And the
unique thing about fifth
is that we can use it to treat MRSA.
Now, the adverse effects for cephalosporins
are going to look familiar to you,
and compared to the other
antibiotics that we discuss.
So, allergic reactions and possible anaphy-
laxis are some of the top reactions.
However, there are some that
are unique to cephalosporins.
2 of the cephalosporins, cefotetan
can interfere with a vitamin K metabolism,
and that puts your patient
at risk for bleeding.
Okay, that's a really unusual
side effect for an antibiotic,
so make sure you star that
one in your notes
for these 2 particular cephalosporins
that can cause bleeding for your patients
because it interferes with
vitamin K metabolism.
Remember, vitamin K metabolism
is really important,
and we'll talk about that more
when we get with warfarin.
That's another drug that we
use as a blood thinner.
So, we have, A, for allergic reaction
or a possible anaphylaxis,
then you've got, B, for bleeding,
and C for thrombophlebitis, that means clots.
So, if we have someone who
ends up with a phlebitis,
that puts someone at a risk for clots
if it's IV infused.
So, for the cephalosporins that
are IV infused, watch for the
possibility of thrombophlebitis, which
could produce a clot for your patient.
Now, this is a rare side effect,
but hemolytic anemia
can be a possible adverse effect
for a cephalosporin.
Hemolytic means -- that's -- breaks
open those red blood cells.
It's very rare, but we just want to make
you aware that it is a possibility.
Now, cephalosporins and alcohol do not mix.
We also talked about this in our
Adverse Effects video,
but we want to hit it again in this one,
because if cefotetan or ceftriaxone
are concurrent with alcohol,
you have that disulfiram effect.
Remember that disulfiram is a drug that
people who are trying to get
over the use of alcohol,
the abuse of alcohol, take it on a
daily basis, because if they mix
the drug and alcohol, they have
a really nasty effect.
End up with severe flushing,
and nausea, vomiting,
possibly even tachycardia and
a low blood pressure.
That's because the combination of
the cephalosporin and alcohol
will cause acetaldehyde to
accumulate in your blood.
So, you want to make sure that you
educate your patients that they should not
drink alcohol when they're
on a cephalosporin.