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. 2019 Oct 31;10:2470. doi: 10.3389/fmicb.2019.02470

TABLE 1.

The penicillins; their chemical groups and subtle differences in modes of action (MOA) against bacterial cell wall biosynthesis (Patrick, 2013).

β-lactam penicillins, COR-substituted 6-aminopenicillanic acid (acyl derivatives of 6-APA)

Sub-group Benzylpenicillin Aminopenicillins Carboxypenicillins Ureidopenicillins Acid-resistant Penicillinase-resistant Penicillin prodrug
Sub-structure 6-benzyl substituted 6-amino substituted α-carboxy substituted α-urea substituted 6-electron withdrawal substituted 6-steric shield substituted Ampicillin esters of carboxyl moiety

MOA Cell wall, inhibition of transpeptidase enzyme

Sub-MOA Lipophilic, but unstable in stomach acid Broad spectrum, higher hydrophilicity, crosses Gram-negative cell wall Stable in stomach acid Blocks β-lactamase Ampicillin has poor absorption, esters aid absorption and are hydrolyzed in phase-1 metabolism

Inhibition Bactericidal

Examples Penicillin G Ampicillin, Amoxicillin, Penicillin N, Penicillin T Carbenicillin, carfecillin (prodrug), ticarcillin Azlocillin, mezlocillin, piperacillin Penicillin V, ampicillin, amoxicillin Methicillin, nafcillin, temocillin, oxacillin, cloxacillin, flucloxacillin, dicloxacillin Pivampicillin, talampicillin, bacampicillin