Evaluation of Agar Dilution Method for Determination of Sensitivity of Bacteria to Antibiotics.

Abstract

98 strains of bacteria were tested for sensitivity to penicillin, bacitracin, streptomycin, chloramphenicol, aureomycin, and terramycin by 3 methods, agar dilution, agar diffusion, and tube dilution. The agar dilution and tube dilution methods of determining bacterial sensitivity are equally reliable. Aureomycin-containing plates can be stored for 3 wks. without loss of potency; plates containing penicillin, bacitracin, streptomycin, chloramphenicol, and terramycin can be stored for 4 wks. without loss of potency. The agar diffusion method of sensitivity detn. is not fully reliable, as shown by poor correlation of the results obtained by that method and the bue dilution method of testing with some antibiotics.