Table 2. Drug resistance characteristics of 12 meat-derived Clostridium difficile isolates determined by E-test on Muller-Hinton agar after 48 h of incubation*.
| Antimicrobial drug | MIC50, μg/mL | MIC90, μg/mL | Range, μg/mL | % Resistant isolates |
|---|---|---|---|---|
| Vancomycin | 0.5 | 0.75 | 0.5 to 1.0 | 0 |
| Metronidazole | 0.38 | 0.5 | 0.19 to 1.0 | 0 |
| Levofloxacin | 32 | 32 | 4 to >32 | 100 |
| Clindamycin | 16.0 | 24.0 | 8 to >256 | 100 |
*Breakpoints used were vancomycin susceptible, <4.0 μg/mL; vancomycin resistant >32.0 μg/mL; metronidazole susceptible, <8.0 μg/mL; metronidazole resistant, >32.0 μg/mL; clindamycin susceptible, <2.0 μg/mL; clindamycin resistant >8.0 μg/mL; levofloxacin susceptible, <2.0 μg/mL; levofloxacin resistant, >8.0 μg/mL.