Table 1.
Antibiotic susceptibility profile of major Singaporean hospital MRSA clones
| Sequence type | SCCmec | No. of isolates tested | Vancomycin (MIC50/90 mg/l) | Gentamicin (MIC50/90 mg/l) | Erythromycin (MIC50/90 mg/l) | Clindamycin (MIC50/90 mg/l) | Ciprofloxacin (MIC50/90 mg/l) | Cotrimoxazole (MIC50/90 mg/l) |
|---|---|---|---|---|---|---|---|---|
| 5 | IV | 7 | Susceptible (1/−) | Susceptible (0·5/−) | Variable (⩾32/−) | Susceptible* (0·125/−) | Resistant (⩾16/−) | Resistant (⩾32/−) |
| 22 | IV | 183 | Susceptible (0·5/1) | Susceptible (0·25/0·5) | Variable (⩾32/ ⩾ 32) | Susceptible* (0·125/0·25) | Resistant (⩾16/ ⩾ 16) | Susceptible (⩽0·25/ ⩽ 0·25) |
| 30 | IV | 8 | Susceptible (0·5/−) | Susceptible (0·5/−) | Susceptible (0·25/−) | Susceptible (0·125/−) | Susceptible (0·5/−) | Susceptible (⩽0·25/−) |
| 45 | IV | 28 | Susceptible (0·5/1) | Variable (⩾32/ ⩾ 32) | Variable (⩾32/ ⩾ 32) | Variable* (0·125/ ⩾ 16) | Resistant (⩾16/ ⩾ 16) | Variable (⩽0·25/16) |
| 239 | III | 256 | Susceptible (1/1) | Resistant (⩾32/ ⩾ 32) | Resistant (⩾32/ ⩾ 32) | Variable* (⩾16/ ⩾ 16) | Resistant (⩾16/ ⩾ 16) | Resistant (⩾32/ ⩾ 32) |
*
Isolates susceptible to clindamycin via minimum inhibitory concentration (MIC) criteria possess inducible resistance to the drug on disk diffusion testing.