ANTIBIOTIC ASSAY MEDIUM NO. 37 (SOYA CASEIN DIGEST MEDIUM) (TRYPTONE SOYA BROTH)

Grove and Randall have elucidated the antibiotic assays and medias in their comprehensive treatise on antibiotic assays. Antibiotic Assay Medium No. 37 can be used as a general medium for sterility checking of pharmaceutical products and cultivation of fastidious and non-fastidious organisms and is formulated as per CFR and USP. It is also used for the sensitivity testing by the tube dilution method for antimicrobial agents.
Turbidimetric antibiotic assay is based on the change or inhibition of growth of a test microorganims in a liquid medium containing a uniform concentration of an antibiotic. After incubation of the test orgainism in the working dilutions of the antibiotics, the amount of growth is determined by measuring the light transmittance using spectrophotometer. The concentration of antibiotic is determined by comparing amounts of growth obtained with that given by the reference standard solutions. Use of this method is appropriate only when test samples are clear.

for sterility testing and cultivation of fastidious and non-fastidious microorganisms