Table 2. Minimum inhibitory concentrations (MICs) and antimicrobial resistance in isolates of Escherichia coli resistant to extended-spectrum cephalosporins isolated by selective screening of faceal swabs from wild red foxes (n = 17) in 2016 in Norway.
| Distribution (n) of MIC values (mg/L) | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Substance | n resistant | 0.015 | 0.03 | 0.06 | 0.125 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | 64 | 128 | 256 | ≥ 512 |
| TET | 3 | 14 | 1 | 2 | |||||||||||||
| TGC | 1 | 15 | 1 | 1 | |||||||||||||
| CHL | 0 | 17 | |||||||||||||||
| AMP | 17 | 17 | |||||||||||||||
| CTX | 17 | 2 | 5 | 2 | 8 | ||||||||||||
| CAZ | 17 | 2 | 2 | 4 | 8 | 1 | |||||||||||
| MER | 0 | 17 | |||||||||||||||
| SXT | 4 | 12 | 1 | 4 | |||||||||||||
| TMP | 3 | 10 | 4 | 3 | |||||||||||||
| AZM | ND | 5 | 7 | 3 | 2 | ||||||||||||
| GEN | 1 | 10 | 5 | 1 | 1 | ||||||||||||
| CIP | 3 | 11 | 3 | 1 | 1 | 1 | |||||||||||
| NAL | 2 | 15 | 2 | ||||||||||||||
| CST | 0 | 17 | |||||||||||||||
Bold vertical lines denote epidemiological cut-off values for resistance. ND = cut-off not defined by EUCAST. White fields denote range of dilutions tested for each antimicrobial agent. MIC values higher than the highest concentration tested are given as the lowest MIC value above the range. MIC values equal to or lower than the lowest concentration tested are given as the lowest concentration tested. TET = tetracycline, TGC = tigecycline, CHL = chloramphenicol, AMP = ampicillin, CTX = cefotaxime, CAZ = ceftazidime, MER = meropenem, SXT = sulfamethoxazole, TMP = trimethoprim, AZM = azithromycin, GEN = gentamicin, CIP = ciprofloxacin, NAL = nalidixic acid, CST = colistin.