Sulfonate SPS Antibiotic Discs (10x50 sheets, BD)

BACKGROUND
Antibiotic test disks are used for semi-quantitative susceptibility testing of common, fast-growing, and certain fastidious bacteria against antibiotics using the agar diffusion method.

TEST PRINCIPLE
Filter paper disks impregnated with defined amounts of antibiotics are placed on the surface of an appropriate medium (e.g., Mueller-Hinton agar). The agar must first be inoculated with a standardized inoculum (EUCAST recommendation: McFarland 0.5) of a fresh pure culture of the bacterial strain to be tested. After a 24-hour incubation, growth is checked, the inhibition zones around the test disks are measured, and compared with the clinical breakpoints for the various antibiotics tested to determine susceptibility (S - Susceptible at standard exposure, I - Possibly susceptible at increased exposure, R - Resistant). The diameter of the inhibition zones corresponds to the susceptibility of the tested bacterial strain to the antibiotic concentration at the edge of the inhibition zone. 

You can find various service documents, such as templates with inhibition zone limits for easy evaluation of the agar diffusion test, a collection of guidelines, and application videos in our media library. 

Content and Storage:
Cartridges with 50 test disks each.
Store at 2-8°C.

Note: BD system cartridges are only compatible with BD dispensers (Becton Dickinson).

As an alternative to agar diffusion, we recommend agar dilution, which can be semi-automated, for example, with the MICRONAUT system, and for which there are increasingly more and more precise clinical breakpoints. That is, at least since EUCAST 10.0 (2020), certain antibiotics can only be tested by agar dilution, and no longer by agar diffusion (!). We would be happy to advise you on this and help you find the best solution for you.