ANTIBIOTIC ASSAY MEDIUM NO. 9 (POLYMYXIN BASE AGAR)

This medium is widely recommended for assay of Polymyxin B, Colistimethate sodium and Colistin using Bordetella bronchiseptica as test organims. Carbenicillin assay is also performed using this medium with Pseudomonas aeruginosa. The medium is numerically identical with the name assigned by Groove and Randall.
To perform the antibiotic assay, the Base Agar should be prepared on the same day as the test. For the cylinder method, a base layer of 21 ml is required. Once the base medium has solidified, seed layer inoculated with the standardized culture can be overlaid. Even distribution of the layer is important.

for assay the products containing Polymyxin-B