Major Classes of Antibiotics Clinical Microbiology Review 224
REPRESENTATIVE
CLASS ANTIBIOTICS MODE OF ACTION SPECTRUM OF ACTIVITY OTHER
Natural penicillins
Synthetic penicillins
Cephalosporins
Carbapenems
Monobactams
b-Lactam. Bactericidal.
Allergic rxn common side
effect.
b-Lactam. Bactericidal.
Penicillinase-resistant
penicillins = oxacillin, methi-
cillin, nafcillin, cloxacillin,
dicloxacillin. Drug class of
choice for staph infections.
b-Lactam. Bactericidal.
b-Lactam. Bactericidal.
Reserved for IV use in serious
infections.
b-Lactam. Bactericidal.
Inhibit cell wall synthesis
Inhibit cell wall synthesis
Inhibit cell wall synthesis
Inhibit cell wall synthesis
Inhibit cell wall synthesis
Penicillin V,
penicillin G
Methicillin, oxacillin,
ampicillin, carbeni-
cillin, piperacillin
Cephalexin, cefo-
toxin, ceftriaxone,
cefepime
Imipenem
Aztreonam
Narrow. GPs other than
staph, some GN.
Broader spectrum of activity
than natural penicillins.
GPs (not MRSA) & GNs.
GPs & GNs. Each genera-
tion has broader spectrum
of activity than previous.
GPs & GNs, including
P. aeruginosa& anaerobes,
but not MRSA or VRE.
P. aeruginosa & other GNR.
Low activity against GPs &
anaerobes.
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