TABLE 1.

Characteristics of clindamycin induction test phenotypes as tested by disk diffusion

Induction test phenotypeResistance phenotypeCLI resultERY resultInduction test description
DInducible MLSBSRBlunted, D-shaped clear zone around CLI disk proximal to the ERY disk (Fig. 1A).
D+Inducible MLSBSRBlunted, D-shaped zone around CLI disk proximal to the ERY disk and small colonies growing to CLI disk in otherwise clear zone (Fig. 1B).
NegMSBSRClear zone around CLI disk (Fig. 1C).
HDConstitutive MLSBRRTwo zones of growth appear around the CLI disk. One zone is a light, hazy growth extending from the CLI disk to the second zone where the growth is much heavier. The inner, hazy zone is blunted proximal to the ERY disk as in phenotype D (Fig. 1D).
RConstitutive MLSBRRNo hazy zone. Growth up to CLI and ERY disks (Fig. 1E).
SNo resistanceSSClear, susceptible zone diameters (Fig. 1F).