These discs are used in qualitative susceptibility testing procedures in
culture media. They serve as a convenient method for addition of antimicrobial
agents to culture media, especially for qualitative studies of mycobacteria and
related organisms.
Certain susceptibility test discs, i.e., streptomycin, 10 µg, kanamycin, 30
µg and rifampin, 5 µg, are also recommended for use in this
procedure.1,2
The discs are added to measured amounts of liquified agar medium, e.g.,
Middlebrook and Cohn 7H10 Agar or Seven H11 Agar, to prepare recommended
concentrations of the antimicrobial agent in solidified agar.2
Falcon™ four compartment X Plate™ Petri
dishes may be used with these discs. Three sections may be employed for various
agents or differing concentrations of the same agent and the fourth section as a
drug-free control.