A disk diffusion test used to study the macrolide lincosamide streptogramin resistance (MLSB), both constitutive and inducible, as well as macrolide streptogramin resistance (MSB) in Staphylococcus aureus. This applies to macrolides (such as erythromycin) inducing resistance to the lincosamide, clindamycin. This resistance mechanism could not be detected if clindamycin was tested alone. The ‘D’ refers to the shape of the zone around the clindamycin disk which is flattened on one side giving a ‘D’ shape.