beta lactams spectrum
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Beta Lactam Antibiotic Spectrum of Activity
Table 1. Penicillins ( + usually effective clinically; +/- clinical trials lacking or only
30-60% sensitivity rate; 0 not effective clinically or
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Table 2. Penicillin/beta lactamase inhibitor combinations
Name streptococci enterococcus
Staph.
aureus(methicillin S)
MRSA1
H.
influenzae
Moraxell
aspecies
Neisseri
aspecies
Non-
pseudomonas aerobicg- rods
Pseudomon
asaeruginosa
Anaerobes
Ampicillin/sulbactam (IV);
Amoxicillin/clavulanate (PO)
+ + + 0 + + + + 0 +
Ticarcillin/clavulanate (IV) + + + 0 + + + + + +
Piperacillin/tazobactam (IV)2 + + + 0 + + + + + +
2Due to the greater intrinsic activity of piperacillin against aerobic gram negative rods,
piperacillin/tazobactam is more effective against gram negative rods than
ampicillin/sulbactam or Ticarcillin/clavulanate. However, the beta lactamase inhibitorsare not effective at inhibiting the chromosomal beta lactamases of Pseudomonasspecies, so the combination drugs have no therapeutic advantage over the beta lactamdrug alone versus Pseudomonas.
Table 3. Cephalosporins (note: although the chart shows most of the
cephalosporins to be significantly active vs Staph. aureus there are relative degrees ofactivity, i.e., the general trend is for 1st generation agents to be more active against
gram positives and later generations to be more active vs gram negatives; cefepime isthe exception having excellent gram positive and gram negative activitiy; likewise,although the chart shows most cephalosporins to have anaerobic activity for oralanaerobes and clostridia species, only cephamycins have useful Bacteroides fragilisactivity and from a practical standpoint cephalosporins other than cephamycins arerarely chosen for treating anaerobes since better agents are available)
Class Namestreptoc
occienterococ
cus
Staph.aureus
(methicillin S)
MRSA1
H.influen
zae
Moraxella
species
Neisseriaspecies
Non-pseudomonas
aerobic g-rods
Pseudomonas
aeruginosa
Anaerobes
1stgeneration
Cefazolin (IV);Cephalexin (PO)
+ 0 + 0+; not
cephale
xin
+/- 00; some E.
coliandKlebsiel
laOK
0 0
2ndgeneration(truecephalo)
Cefuroxime(IV/PO);cefaclor(PO)
+ 0 + 0 +
+; cefaclor
is +/-
N.gonorrhoeae
+/-; N.meningitidis
+
+/- 0
G.I. tract(B.
fragilis)0
Clostridiaspecies
(not
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difficile) +
Oralanaerobes
+2nd
generation(cephamycin)
Cefoxitin(IV) + 0 + 0 + + +/- + 0 +
3rdgeneration
Ceftriaxone(IV/IM);cefixime(PO)
+ 0 + 0 + + + + +/-
G.I. tract(B.
fragilis)0
Clostridiaspecies
(not
difficile) +
Oralanaerobes
+/-
3rdgeneration(anti-pseudomonas)
Ceftazidime (IV)
+
muchless
activethan
ceftriaxone vs
pneumococci
0 +/- 0 + + +/- + +
G.I. tract(B.
fragilis)0
Clostridiaspecies
(not
difficile) +
Oralanaerobes
+4th
generation
Cefepim
e (IV) + 0 + 0 + + + + + 0
Table 4. Monobactams
Namestreptococc
ienterococcu
s
Staph.aureus
(methicillin S)
MRSA1
H.influenza
e
Moraxella
species
Neisseria
species
Non-pseudomonas aerobic g-
rods
Pseudomonas aeruginosa
Anaerobes
Aztreonam
0 0 0 0 + + + + + 0
Table 5. Carbapenems
Namestreptococ
cienterococc
us
Staph.aureus
(methicilli
MRSA1
H.influenza
e
Moraxella
species
Neisseria
species
Non-pseudomonas aerobic
Pseudomonas
aeruginosa
Anaerobes
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n S) g- rods
Imipenem/cilastatin (IV) +
+; E.faecalis only
+ 0 + + + + + +
Meropenem (IV) ++/-; E.
faecalis only+ 0 + + + + + +
Ertapenem (IV)
+ + 0 + + + + 0 +