TABLE 2.
Free calcium concentration with MIC comparisons of VGS in different media
| Mediuma | Free Ca+ concn | MIC (μg/ml) for the following drug/reference strainb: |
||||
|---|---|---|---|---|---|---|
| DAP/1643 | DAP/1647 | DAP/1648 | DAP/1649 | VAN/1648 | ||
| CA-SMHB | 56.608 | 1 | 2 | 1 | 2 | 0.5 |
| THB | 5.370 | 64 | >64 | 64 | 64 | 2 |
| STHB | 16.565 | 4 | >64 | 64 | 8 | 1 |
| THB+Y | 29.079 | 32 | >64 | >64 | 64 | 1 |
| STHB+Y | 17.133 | 4 | >64 | 16 | 8 | 2 |
| CB | 7.055 | 64 | >64 | >64 | >64 | 0.5 |
| SCB | 16.565 | 8 | 64 | 16 | 16 | 1 |
| BHI | 4.669 | >64 | >64 | >64 | >64 | 1 |
| SBHI | 35.252 | 4 | >64 | 32 | 16 | 1 |
The different media tested were as follows: CA-SMHB, calcium-supplemented Mueller-Hinton broth with 50 mg/liter Ca and 12.5 mg/liter Mg; THB, Todd-Hewitt broth; STHB, Todd-Hewitt broth with 50 mg/liter Ca and 12.5 mg/liter Mg; THB+Y, Todd-Hewitt broth plus 5% yeast extract; STHB+Y, Todd-Hewitt broth with 50 mg/liter Ca and 12.5 mg/liter Mg plus 5% yeast extract; CB, Columbia broth; SCB, Columbia broth with 50 mg/liter Ca and 12.5 mg/liter Mg; BHI, brain heart infusion broth; SBHI, brain heart infusion broth with 50 mg/liter Ca and 12.5 mg/liter Mg.
The drugs were daptomycin (DAP) and vancomycin (VAN). The organisms tested were S. mitis strain 1643, S. oralis strains 1647 and 1648, and S. gordonii strain 1649.