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1. Disk Diffusion Test
The diffusion method is one of the oldest approaches, one of the most commonly used methods
in routine use, Suitable for the majority of pathogenic bacteria including slow-growing bacteria
The purpose of the disk diffusion test is to determine the sensitivity or resistance of pathogenic
aerobic and facultative anaerobic bacteria to various antimicrobial compounds.
The pathogenic organism is grown on Mueller-Hinton agar in the presence of various
antimicrobial impregnated filter paper disks. The presence or absence of growth around the
disks is an indirect measure of the ability of that compound to inhibit that organism.
The EUCAST method is standardized, based on the principles defined in the report of the
International Collaborative Study of Antimicrobial Susceptibility Testing (1972) but also on
the experience of experts from around the world.
Figure 36 : Disc diffusion test