kram welcome to another MedCram lecture we're going to talk about cephalosporins
and specifically the different generations of cephalosporins
some representative antibiotics in each class and what are the unique things
about those generations and what they do in their coverage so there are five
generations of cephalosporins we've got the first generation cephalosporin we've
got the second which we'll talk about the third which is the workhorse of the
pneumonia scene we've got the fourth generation which has got the Pseudomonas
coverage so also in the third and then finally the fifth which is an
interesting generation that we'll talk about the first generation of
cephalosporins as we go from first the second to third
to fourth you'll see that there is better and better gram-negative coverage
so at the very beginning with the first generation cephalosporins we have
medications like cefazolin and cephalexin and these antibiotics really
have no anaerobic coverage so no an aerobic coverage but what they did have
a lot of coverage for is gram-positive so this is this is going to be our
gram-positive box and this is going to be our gram-negative box so in terms of
gram positives it had really good staff and actually pretty good strap coverage
so where do we see these things being used we see these things being used in
for instance skin infections because this has got really good gram-positive
coverage no anaerobic coverage good staph and strep and in terms of
gram-negative it would still take care of you know your regular gram negatives
like e.coli like Proteus and like Klebsiella okay when they went on to
second generation cephalosporin here we're talking about medications
like cefuroxime and likes fot ten so the biggest thing about this was that now we
had an aerobic coverage that was the big thing and so as a result of that we're
now we're looking at intra-abdominal and the reason why we could do that was
because there's a lot of anaerobic bacteria intra-abdominal ewwww
but in terms of the staph and strep it stayed the same going from the first
generation to the second there was really no change so we didn't lose much
in terms of staph and strep but going from first generation the second
generation we actually got a little bit better gram-negative coverage so that's
what really made it really well in terms of intra-abdominal infections the second
generation was better in terms of that okay let's go on to the third generation
third generation cephalosporins there's three major examples and you should know
these one of them is ceftriaxone the other one is cefotaxime and the last
one is a very important one called ceftazidime we'll talk about that one a
little bit in terms of anaerobic coverage well it lost it again
so not anaerobic no anaerobic coverage here whereas we had it back in the
second generation now in terms of gram positives here it was okay definitely
very good in pneumococcus okay but in terms of staff probably not as good a
coverage in terms of staph aureus because it has good pneumococcal
coverage third-generation cephalosporins were really good at lung lung infection
so we're talking about community-acquired pneumonia now this
couple things I should mention here and that's very specifically that
ceftazidime is
covering Pseudomonas and that's an important thing that we're going to have
to bring up here when we talk about gram negatives is that here it's even better
you can see as we go up the list here in terms of generations that the gram
negative coverage just keeps getting better
specifically if you're using ceftazidime you can now cover Pseudomonas but even
if you're not we're talking good coverage with Neisseria gonorrhea we're
talking about enterobacter ishe so enterobacter we're talking about
Serratia so Enterobacter Serratia a Neisseria gonorrhea it's better and
here's the big one if you use ceftazidime it'll cover Pseudomonas now
that's a big one because Pseudomonas is the infection that people get in nursing
homes specifically in their lung so that's third generation probably one of
the best up to that point in terms of gram-negative coverage now fourth
generation the big one that you got to know there is cefepime now cefepime is
important because it also covers the big p the big Pseudomonas okay in terms of
anaerobic coverage still no anaerobic coverage so so far the only one that
actually covers anaerobes is the second generation cephalosporins now the fourth
generation cephalosporins were something quite amazing because what it did is it
took the strength of the first generation for gram positives
okay so really strong and it added the great gram-negative coverage of the
third and made it strong so cefepime is really outstanding and so what were we
using these for we were using these for very serious infections anywhere so I'll
put serious here because it's got excellent coverage strong gram-positive
strong gram-negative and the extra bonuses it covers Pseudomonas so we can
think of like for instance immuno compromised patients or fever of unknown
origin okay so this fourth generation cephalosporin had excellent excellent
coverage now when we go to the fifth generation the fifth generation
cephalosporin is kind of unusual because we've got different players in that
generation which are very very different from each other the first one that I
want to talk to you about is a long one called satola zane and it actually is
combined with taser back town which is a beta-lactamase inhibitor okay septal is
a nasal backed ham and the other one is seft Arlene these are very different 5th
generation cephalosporins again for the second time we have good anaerobic
coverage you should know that it's really just the second generation and
the fifth generation that have an aerobic coverage but let's talk a little
bit more about these two players ACEF Tala Zane kaizo back down this
first one what they did was they took ceftazidime okay that structure and they
basically made it better and so that this is the actually the most potent
anti Pseudomonas F less foreign that we currently have and they added on a Tazo
back Tam which is a beta-lactamase inhibitor so this is a super anti
Pseudomonas that works well so just to review we've got three cephalosporins
that have anti sunomono coverage and I think that's important to know you
should know that ceftazidime cefepime and seth tall is a nar now we use
ceftriaxone as our third-generation cephalosporin to treat
community-acquired pneumonia notice that ceftriaxone or Rocephin does
not have any anti sunomono coverage so if a patient is coming in from a nursing
home or some institution or a hospital that they're at risk for having
Pseudomonas you should not use ceftriaxone do not use ceftriaxone
because ceftriaxone has no anti-suit ammonal coverage the only one that has
anti Pseudomonas coverages is ceftazidime cefepime and septal is Ain
okay so this is a great anti Pseudomonas medication now what is left orally what
is so good about it actually satara lean fluoro is the trade name actually covers
em are SI it is the only cephalosporin that can actually treat mr si okay so
that's pretty important it's currently indicated for skin and soft-tissue
infections and also community acquired pneumonia it has not as of this taping
gotten the FDA approval for Mrs a pneumonia one other bit of advice
information I want to give you is sometimes when they're actually testing
bacteria like gram negatives for cefepime they'll notice that it is
sensitive to cefepime but it's not sensitive to any other cephalosporin
this you should think about in terms of if it is possible to be an extended
spectrum beta-lactamase if they are you should not use any cephalosporins
whatsoever and switch to the mono lactam and we'll talk about that in one of our
next lectures so just to review again here we've got the first second third
fourth and fifth generation the first generation was really good on gram
positive staph and strep did not have anaerobic coverage and had so-so
gram-negative coverage really good for skin and
actions like cefazolin cephalexin okay but because it had good gram-negative
coverage like e-coli you could use it in simple urinary tract infections going to
second generation we've got an aerobic coverage we've got better gram-negative
coverage this is intra-abdominal because of that anaerobic and better
gram-negative coverage third generation is the workhorse for community-acquired
pneumonia because of the ceftriaxone but you should also know that it also holds
ceftazidime which is an anti-suit ammonal and it's got one of the best
gram-negative coverages out of all of the generations four generation took the
best of both worlds it took the first generation gram-positive coverage and it
took the third generation gram-negative coverage put it all together and you got
cefepime which is anti pseudo monel okay so it was for serious infections where
you needed really good broad-spectrum antibiotics finally the fifth generation
has two odd players that are really different from each other
SEF tolas ain which is the anti Pseudomonas what you have to worry about
in a hospital acquired infections but also mr sa coverage with SEF terylene
also something you have to worry about in hospital acquired infections two
different drugs same generation okay well thanks for joining us
you