Table 5. MICs of 8 antimicrobial agents for toxigenic and non-toxigenic C. difficile isolates as determined by using agar dilution.
| Antimicrobial agent | tcdA+/tcdB+ (n = 226 isolates) | tcdA-/tcdB- (n = 118 isolates) | ||||||
|---|---|---|---|---|---|---|---|---|
| Range (mg/L) | MIC50 (mg/L) | MIC90 (mg/L) | Resistance (%) | Range (mg/L) | MIC50 (mg/L) | MIC90 (mg/L) | Resistance (%) | |
| Vancomycin | 0.03–1 | 0.25 | 0.5 | 0 | 0.03–1 | 0.25 | 0.5 | 0 |
| Metronidazole | 0.06–0.5 | 0.25 | 0.5 | 0 | 0.03–1 | 0.25 | 0.5 | 0 |
| Fidaxomicin | 0.0075–0.5 | 0.06 | 0.125 | 0 | 0.0075–0.5 | 0.06 | 0.125 | 0 |
| Rifaximin | 0.0009–0.25 | 0.015 | 0.015 | 0 | 0.0009–0.25 | 0.015 | 0.03 | 0 |
| Levofloxacin | 2–128 | 4 | 8 | 40.3 | 2–128 | 4 | 8 | 39.8 |
| Ciprofloxacina | 4–128 | 16 | 16 | 99.6 | 4–128 | 8 | 16 | 95.8 |
| Meropenem | 1–16 | 2 | 4 | 1.8 | 1–16 | 2 | 4 | 0.8 |
| Chloramphenicol | 2–64 | 8 | 16 | 3.5 | 4–64 | 8 | 16 | 0.8 |
a MICs between toxigenic and non-toxigenic C. difficile isolates were compared using Fisher’s exact test (P < 0.05).