Antiseptic/Disinfectant Disc Sensitivity Test:
Disinfectant Sensitivity Disc Test is performed in a similar manner to the
Kirby-Bauer Disc Diffusion Experiment. In this case however, YOU
make the discs! This disk diffusion test is a
non- standardized protocol for determining the PRACTICAL antiseptic and
disinfectant susceptibility of your particular unknown.
A pure culture of the UNKNOWN organism is inoculated on Mueller-Hinton agar. You must create a "lawn or confluent growth area" on the poured cooled agar using a sterile Q-tip dipped into your unknown organism. Swab the entire surface of the agar quickly.
The "disc" are place on this lawn BEFORE incubation. Place the disc no closer than than 2 cm apart using flamed forceps or tweezers and press the discs into the agar gently. Then incubate the plate upside-down at the optimum temperature for 18 hours.
To make the sterile filter-paper disks you obtain sterile filter paper punches and "dip" tem into your chosen test substances (at "use" concentration). The treated filter discs are allowed to dry on a paper towel and then applied to the inoculated agar using sterile forceps are added to the plate (at a distance of no less than 2 cm apart). The plate is then incubated upside-down at optimum temperature for 18 hrs.
After incubation the diameter of any zone of inhibition is reported in millimeters. Results are reported as S (sensitive) or R (resistant).
See the Handbook page 113-1 (NO LONGER USED) for information on the Antiseptic/Disinfectant Disc Diffusion Experiment... USE ATLAS OR ONLINE!
Click below on the BLUE BUTTON TO GO A CERTAIN PAGE...