Inhibition of folate synthesis. Inhibition of cell wall synthesis. Inhibition of nucleic acid synthesis. Agents which damage membranes. The organism is now resistant to Pen G. 4.
Penicillins are generally bacteriocidal at clinically relevant doses.
Erythromycin can be bacteriostatic or bacteriocidal at clinically relevant doses. Tetracyclines can be bacteriostatic or bacteriocidal at clinically relevant doses. In an immunocompromized host, bacteriocidal agents are preferred over bacteriostatic agents. If phenoxyacetic acid was incorporated instead of phenylacetic acid, Pen V would result. The structure shown is amoxicillin.