Table 3.
Minimal inhibitory concentrations (MIC50 and MIC90) of ophthalmic antibiotics for the most prevalent bacterial genera isolated in dogs with bacterial keratitis.
| Staphylococcus sp. (n = 123) | Streptococcus sp. (n = 68) | Pseudomonas sp. (n = 44) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MIC50 | MIC90 | Susceptible | Resistant | MIC50 | MIC90 | Susceptible | Resistant | MIC50 | MIC90 | Susceptible | Resistant | |
| Amikacin | ≤16 | ≤16 | 98% | 0% | >32 | >32 | 16% | 53% | ≤16 | ≤16 | 93.2% | 0.0% |
| Bacitracin | >4 | >4 | 0% | 41% | >4 | >4 | 0% | 0% | >4 | >4 | 0.0% | 0.0% |
| Cefazolin | ≤8 | ≤8 | 7% | 10% | ≤8 | ≤8 | 9% | 3% | >16 | >16 | 0.0% | 81.8% |
| Ceftiofur | ≤2 | ≤2 | 88% | 7% | ≤2 | ≤2 | 99% | 1% | >4 | >4 | 20.5% | 79.5% |
| Chloramphenicol | ≤4 | >16 | 88% | 12% | ≤4 | ≤4 | 100% | 0% | >16 | >16 | 20.5% | 77.3% |
| Ciprofloxacin | ≤1 | >4 | 79% | 20% | ≤1 | 2 | 47% | 3% | ≤1 | ≤1 | 95.5% | 2.3% |
| Doxycycline | 0.25 | >2 | 54% | 0% | 0.25 | >2 | 35% | 0% | >2 | >2 | 27.3% | 0.0% |
| Erythromycin | ≤0.5 | >4 | 59% | 39% | ≤0.5 | 2 | 1% | 15% | >4 | >4 | 0.0% | 4.5% |
| Gentamicin | ≤2 | >8 | 72% | 20% | 8 | >8 | 41% | 13% | ≤2 | ≤2 | 97.7% | 0.0% |
| Moxifloxacin | ≤0.5 | >1 | 80% | 17% | ≤0.5 | ≤0.5 | 1% | 0% | 1 | 1 | 0.0% | 0.0% |
| Neomycin | ≤4 | >8 | 89% | 11% | >8 | >8 | 19% | 79% | ≤4 | 8 | 93.2% | 4.5% |
| Ofloxacin | 0.5 | >1 | 80% | 14% | 1 | >1 | 46% | 0% | 0.5 | 1 | 45.5% | 0.0% |
| Oxytetracycline | 1 | >4 | 54% | 22% | 2 | >4 | 63% | 22% | >4 | >4 | 40.9% | 38.6% |
| Polymyxin B | 10 | >10 | 0% | 36% | >10 | >10 | 0% | 56% | ≤5 | ≤5 | 0.0% | 0.0% |
| Ticarcillin | ≤16 | ≤16 | 40% | 7% | ≤16 | ≤16 | 56% | 0% | ≤16 | 64 | 63.6% | 6.8% |
| Tobramycin | ≤4 | 16 | 76% | 14% | 8 | 16 | 6% | 24% | ≤4 | ≤4 | 100.0% | 0.0% |
| Trimethoprim-Sulfamethoxazole | ≤2 | >2 | 74% | 26% | ≤2 | ≤2 | 18% | 0% | >2 | >2 | 18.2% | 20.5% |