Table 1.
Phenotypic groupings and their features in the D test.
| Phenotype | Resistance Phenotype | CLI Result | ERY Result | Double Disc Diffusion Test Description |
|---|---|---|---|---|
| D+ | Inducible MLSB | S | R | Flattened, D-shaped clear zone around the CLI disc close to resistant ERY disc |
| D− | MS | S | R | Susceptible zone around the CLI disc and resistant zone around ERY disc |
| R | Constitutive MLSB | R | R | Resistance zones around the CLI and ERY discs |
| S | No Resistance | S | S | Susceptible clear zones around both discs |
S, sensitive; R, resistant; D+, D test positive; D−, D test negative; CLI, clindamycin; ERY, erythromycin; MLSB = macrolide-lincosamide-streptogramin B; MS, macrolide-streptogramin.