The in Vitro Effect of Penicillin

The exceptionally powerful inhibitory effect of penicillin on the growth of the gonococcus in vitro has already been reported.¹The current study was undertaken to evaluate these findings and to determine specifically whether or not there was any difference in the antibacterial action of penicillin against sulfonamide resistant and sulfonamide susceptible gonococcus strains. An attempt was also made to study the effect of combined "subtherapeutic" doses of sulfathiazole and penicillin on sulfonamide resistant strains. The object of this experiment was to see whether the combined antibacterial action of these two agents would be effective when the action of each individual agent was not sufficient to kill off the organisms. TECH NIC The technic followed in these test tube experiments was identical with that previously described for the in vitro differentiation of sulfonamide susceptible and resistant strains, with the only difference that pencillin²was substituted for sulfathiazole.³The