Volume 11, Number 3—March 2005
Research
Methicillin-resistant Staphylococcus aureus in Horses and Horse Personnel, 2000–2002
Table
In vitro antimicrobial susceptibilities of 101 methicillin-resistant Staphylococcus aureus isolates from humans and horses*
| Antimicrobial agent | MIC in μg/mL |
% of isolates |
|||
|---|---|---|---|---|---|
| 50% | 90% | Range | Intermediate | Resistant | |
| Tetracycline | >16 | >16 | <4–>16 | 0 | 96 |
| Doxycycline | 8 | 8 | <4–8 | 78.2 | 0 |
| Minocycline | <4 | <4 | <4–8 | 14.8 | 0 |
| Erythromycin | >8 | >8 | <0.5–>8 | 0 | 86.1 |
| Gentamicin | >16† | >16† | <2–>16† | 9.9 | 88.1 |
| Rifampicin | >4 | >4 | <1–>4 | 10.9 | 71.2 |
| TMP/SMX | 8/152 | >8/152 | <2/38–8/152 | NA | 79.2 |
*MIC, minimum inhibitory concentration; TMP/SMX, trimethoprim-sulfamethoxazole; NA, no intermediate MIC category in NCCLS guidelines.
†All strains were susceptible to gentamicin at a concentration of 500 μg/mL.


