Action of caffeine and theophylline on staphylococcal penicillinase synthesis

Both caffeine and theophylline acting in subinhibitory concentrations inhibit the synthesis of penicillinase in Staphylococcus aureus. Neither of these compounds inactivate the enzyme. Inhibition of penicillinase synthesis is attributed to the lack of formation of penicillinase rather than the elimination of the extrachromosomal plasmid.