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Table 12-5

Review of Selected Beta-Lactam Antibiotics

β-lactam classβ-lactam (and β-lactamase inhibitor)Gram Pos aGram NegPseudomonasCovered organisms
NaturalPenicillin G±--Treponema pallidum, meningococcal meningitis
Penicillinase resistant(Methicillin) Nafcillin Oxacillin++--penicillin-resistant MSSA, streptococci
AminopenicillinsAmpicillin, Amoxicillin+±-Streptococci, enterococci
with Sulbactam or Clavulanate+++-Above and penicillin- resistant MSSA, anaerobes, some Enterobacterales
UreidopenicillinsPiperacillin+++Streptococci, enterococci
with Tazobactam+++++Above and penicillin- resistant MSSA,
anaerobes, some Enterobacterales

++, highly active; +, active; ±, limited activity; -, not active; MSSA, methicillin-sensitive Staphylococcus aureus; Neg, negative; Pos, positive.

aTherapy with β-lactams in the setting of gram-positive nosocomial infections should be guided by culture data owing to variable rates and patterns of resistance.