Table 2.
Activity of selected antimicrobial agents against recent isolates of MRSA from the U.S. hospitals
| Drug | Nasal isolates |
Blood isolates |
P valuea | ||||||
|---|---|---|---|---|---|---|---|---|---|
| MIC |
% resistant | MIC |
% resistant | ||||||
| 50% | 90% | Range | 50% | 90% | Range | ||||
| Amikacin | 8 | 32 | ≤1–>64 | 5.4 | 8 | 32 | ≤1–>64 | 2.1 | >0.05 |
| Ciprofloxacin | >8 | >8 | ≤0.12–>8 | 83.6 | >8 | >8 | ≤0.12–>8 | 81.4 | >0.05 |
| Clindamycin (not induced) | 0.25 | >8 | ≤0.06–>8 | 48.8 | 0.125 | >8 | ≤0.06–>8 | 39.7 | 0.052 |
| Clindamycin (after induction) | 67.6 | 48.5 | <0.001 | ||||||
| Daptomycin | 1 | 1 | 0.25–1 | 0.0 | 1 | 1 | 0.5–2 | 1.5 | >0.05 |
| Erythromycin | >16 | >16 | 0.25–>16 | 89.3 | >16 | >16 | 0.25–>16 | 88.1 | >0.05 |
| Gentamicin | 0.5 | 1 | ≤0.12–>16 | 3.0 | 0.5 | 1 | ≤0.12–>16 | 4.1 | >0.05 |
| Levofloxacin | >8 | >8 | ≤0.06–>8 | 81.3 | 4 | >8 | ≤0.06–>8 | 76.8 | <0.01 |
| Linezolid | 2 | 4 | 1–4 | 0.0 | 2 | 4 | 1–4 | 0.0 | >0.05 |
| Moxifloxacin | 4 | >4 | ≤0.03–>4 | 69.9 | 2 | >4 | ≤0.03–>4 | 56.2 | >0.05 |
| Mupirocin | ≤4 | ≤4 | ≤4–>512 | 3.3 | ≤4 | 8 | ≤4–>512 | 5.2 | >0.05 |
| Nitrofurantoin | 16 | 16 | 4–>128 | 0.3 | 16 | 16 | 8–64 | 0.0 | >0.05 |
| Oxacillin | >32 | >32 | 4–>32 | 100 | 16 | >32 | 4–>32 | 100 | >0.05 |
| Tetracycline | ≤0.25 | 0.5 | ≤0.25–>32 | 4.3 | ≤0.25 | 0.5 | ≤0.25–>32 | 4.6 | >0.05 |
| Tigecycline | 0.125 | 0.25 | 0.016–0.5 | 0.0 | 0.125 | 0.25 | 0.06–0.5 | 0.0 | >0.05 |
| Tobramycin | >16 | >16 | 0.25–≥16 | 55.9 | 1 | >16 | ≤0.12–>16 | 36.6 | <0.001 |
| Trimethoprim-sulfamethoxazole | ≤0.125/2.375 | 0.25/4.75 | ≤0.125/2.375–>16/304 | 5.4 | <0.125/2.375 | 0.25/4.75 | ≤0.125/2.375–>16/304 | 6.2 | >0.05 |
| Vancomycin | 0.5 | 1 | 0.25–1 | 0.0 | 0.5 | 1 | 0.5–2 | 0.0 | >0.05 |
a
P values determined using Fisher's exact test.