Antistaphylococcal Activity of Sodium Methicillin:  2,6-Dimethoxyphenyl Penicillin; Penicillin X-1497

Introduction  Several British investigators have published preliminary observations with a new penicillin which is active against penicillin-ase-producing staphylococci.^1-10Our studies of this penicillin, sodium methicillin (penicillin X-1497 or sodium 2,6-dimethoxyphenyl penicillin monohydrate), have included comparisons of the bacteriostatic and bactericidal activities of methicillin, penicillin G, penicillin V, and phenethicillin (penicillin 152) against several recently isolated bacterial species; the susceptibility tests of staphylococci were correlated with the activity of staphylococcal penicillinase on 3 penicillins.In addition, measurements were made of the antistaphylococcal activity of serum and transudates after large intramuscular doses of methicillin.A number of hospitalized patients have been treated to determine the effect of methicillin on nasal carriers of staphylococci. Finally, a small group of patients with serious bacterial infections have been treated and observed for toxicity and therapeutic effectiveness.

Materials and Methods  The susceptibility of various bacteria to the 4 penicillins^* was determined by a twofold serial