Studies on Antibiotic Synergism and Antagonism

WITH THE availability of an increasing number of effective antimicrobial agents, there has developed a tendency toward the use of combinations of drugs. Relatively little is known about the effect of the simultaneous administration of two or more chemotherapeutic agents as compared with that of a single one. When several drugs are administered simultaneously, it is with the hope of attaining greater therapeutic efficacy, through either additive or synergistic effects. That such synergism can occur has been demonstrated both experimentally and clinically.¹On the other hand, it has been shown that combinations of certain antibiotics are less efficacious than one of the agents alone. This phenomenon has been called "antibiotic antagonism." In a preceding report from this laboratory the interference of chloramphenicol with the bactericidal and therapeutic action of penicillin was described in detail.²A preliminary communication indicated that aureomycin and terramycin may likewise be "antagonistic" to penicillin