Combined agar diffusion and replica plating techniques with study of antibacterial substances

Much interest has recently been aroused in the field of antibiotics by two distinct but related problems. The first concerns the possibility that in certain types of infection, notably subacute bacterial endocarditis, the bactericidal action of a drug is of greater therapeutic significance than the inhibitory effect (Hunter 1950; Robbins and Tompsett, 1951; Cates, Christie, and Garrod, 1951). The second problem is the action of anti-biotics used in combination. In this respect the findings of many workers indicate that different mixtures may show augmented or diminished bactericidal effect, and the result may be influenced by the species or strain of organism teste