Antibiotic Medium No 8 (Base Agar) 1004 Condalab

Antibiotic Medium Nº 8 is a standard agar base that is used for the microbiological assay of antibiotics like tetracycline due to its lower pH. The activity of an antibiotic is demonstrated under suitable conditions by its inhibitory effect on microorganisms. Reduction in antimicrobial activity may reveal changes not demonstrated by chemical methods. The antibiotic media are identified numerically with names assigned by Grove and Randall in “Assay methods of antibiotics”. The use of standardized culture media and strict control of all test conditions are essential requirements in the microbiological assay of antibiotics to obtain satisfactory test results.

This medium has the same formula as Antibiotic Medium Nº 5 (Cat. 1524) and Antibiotic Medium Nº 2 (Cat. 1002), with the difference that the pH of the medium has been adjusted to 5.7. To carry out the antibiotic test, the Antibiotic Medium should be prepared on the same day as the test is done. The sample can be tested by the two methods of dilution and assay plate diffusion. Gelatin peptone and beef extract provide nitrogen, vitamins, minerals, and amino acids essential for growth. Yeast extract is source of vitamins, particularly the B-group. Bacteriological Agar is the solidifying agent.