Table 2.
Resistance profiles and antibiotic minimal inhibitory concentration (MIC) of the SDSD isolates VSD5, VSD9, VSD13, VSD21, VSD23, and VSD24 and for control S. pyogenes isolate GAP58
| Isolate codea | Resistance phenotype | Minimum inhibitory concentration (μg/ml)b | ||
|---|---|---|---|---|
| (by disc difusion) | TET | GEN | ERY | |
| VSD5 | TET | 64 | 2 | nd |
| VSD9 | TET | 16 | 2 | nd |
| VSD13 | TET + cMLSB | 16 | 2 | >1,000 |
| VSD21 | TET+ GEN + cMLSB | 16 | 2 | 250–500 |
| VSD23 | TET+ GEN | 16 | 2 | nd |
| VSD24 | GEN | 4 | 4 | nd |
| GAP58 | TET | 16 | 2 | nd |
a
VSD5, VSD9, and VSD13 were collected in 2002–2003 and VSD21, VSD23, VSD24 were collected in 2011–2013.
b
TET, GEN, ERY—Resistant to tetracycline, gentamicin, and erythromycin, respectively. cMLSB only: constitutive MLSB resistance phenotype only; cMLSB + TET: constitutive MLSB resistance phenotype and resistance to tetracycline.