TABLE 3.
MICs for MDR S. enterica serovar Typhimurium strains and their ramA knock-out mutants
| Salmonella strain | MIC (mg/liter)
|
||||||||
|---|---|---|---|---|---|---|---|---|---|
| Amoxicillin | Gentamicin | Doxycycline | Trimethoprim | Tetracycline | Flumequine | Ciprofloxacin | Florfenicol | Chloramphenicol | |
| 14028s | 1 | 1 | 2 | ≤0.5 | 1 | ≤0.5 | <0.06 | 4 | 8 |
| 14028s ΔramA | 1 | 1 | 2 | ≤0.5 | 1 | ≤0.5 | <0.06 | 4 | 8 |
| MDR strains | |||||||||
| 1 | >32 | ≤0.25 | 16 | ≤0.5 | 32 | ≤0.5 | <0.03 | 128 | >128 |
| 1 ΔramA | >32 | 0.5 | 16 | ≤0.5 | 24 | ≤0.5 | <0.06 | 64 | >128 |
| 2 | >32 | ≤0.25 | 16 | >64 | >256 | 1 | <0.06 | 128 | >128 |
| 2 ΔramA | >32 | 0.5 | 8 | >64 | 48 | ≤0.5 | <0.06 | 32 | >128 |
| 3 | >32 | 0.5 | 16 | ≤0.5 | 96 | ≤0.5 | <0.03 | 128 | >128 |
| 3 ΔramA | >32 | 0.5 | 4 | ≤0.5 | 24 | ≤0.5 | <0.06 | 64 | >128 |
| 4 | >32 | ≤0.25 | 16 | ≤0.5 | 32 | 1 | <0.03 | 32 | >128 |
| 4 ΔramA | >32 | 1 | 8 | ≤0.5 | 24 | ≤0.5 | <0.06 | 32 | >128 |
| 5 | >32 | ≤0.25 | 16 | 1 | >256 | 2 | <0.06 | 64 | >128 |
| 5 ΔramA | >32 | ≤0.25 | 8 | ≤0.5 | 24 | ≤0.5 | <0.06 | 16 | >128 |
| 6 | >32 | 0.5 | 16 | ≤0.5 | 32 | 1 | <0.03 | 32 | >128 |
| 6 ΔramA | >32 | ≤0.25 | 4 | ≤0.5 | 32 | ≤0.5 | <0.06 | 32 | >128 |
| 7 | >32 | ≤0.25 | 16 | ≤0.5 | 48 | ≤0.5 | <0.03 | 32 | >128 |
| 7 ΔramA | >32 | 0.5 | 4 | ≤0.5 | 16 | ≤0.5 | <0.06 | 16 | >128 |
| 8 | >32 | 0.5 | 16 | ≤0.5 | 48 | ≤0.5 | <0.03 | 32 | >128 |
| 8 ΔramA | >32 | 0.5 | 8 | ≤0.5 | 24 | ≤0.5 | <0.06 | 16 | >128 |
| 9 | >32 | 0.5 | 16 | ≤0.5 | 96 | ≤0.5 | <0.03 | 32 | >128 |
| 9 ΔramA | >32 | 0.5 | 4 | ≤0.5 | 24 | ≤0.5 | <0.06 | 32 | >128 |
| 10 | >32 | 0.5 | 64 | >64 | 256 | ≤0.5 | <0.03 | 2 | >128 |
| 10 ramA | >32 | 0.5 | 32 | >64 | 256 | 1 | <0.06 | 4 | >128 |
| 11 | >32 | ≤0.25 | 32 | ≤0.5 | >256 | 64 | >4 | 4 | >128 |
| 11 ramA | >32 | 0.5 | 32 | ≤0.5 | 256 | 32 | 8 | 4 | >128 |
| 12 | >32 | ≤0.25 | 16 | ≤0.5 | 48 | ≤0.5 | <0.03 | 64 | >128 |
| 12 ramA | >32 | 0.5 | 8 | ≤0.5 | 32 | ≤0.5 | <0.06 | 16 | >128 |
| 13 | >32 | 0.5 | 32 | >64 | 256 | ≤0.5 | <0.03 | 4 | >128 |
| 13 ramA | >32 | 0.5 | 32 | >64 | 256 | ≤0.5 | <0.06 | 4 | >128 |
| 14 | >32 | ≤0.25 | 16 | ≤0.5 | 96 | 1 | <0.03 | 64 | >128 |
| 14 ramA | >32 | 0.5 | 16 | ≤0.5 | 128 | ≤0.5 | <0.06 | 32 | >128 |
| 15 | >32 | ≤0.25 | 16 | ≤0.5 | 32 | ≤0.5 | <0.03 | 64 | >128 |
| 15 ramA | >32 | 0.5 | 8 | ≤0.5 | 24 | 1 | <0.06 | 32 | >128 |
According to NCCLS guideline M2-A7, the MIC breakpoints are as follows: for amoxicillin (the criteria for ampicillin were used), sensitive, ≤8 mg/liter; resistant, ≥32 mg/liter; for gentamicin, sensitive, ≤4 mg/liter; resistant, ≥8 mg/liter; for doxycycline, sensitive, ≤4 mg/liter; resistant, ≥16 mg/liter; for flumequine (the criteria for oxolinic acid were used), sensitive, ≤4 mg/liter; resistant, ≥8 mg/liter; for tetracycline, sensitive, ≤4 mg/liter; resistant, ≥16 mg/liter (values for tetracycline were determined by E-test); for ciprofloxacin, sensitive, ≤2 mg/liter; resistant, ≥4 mg/liter; for chloramphenicol, sensitive, ≤64 mg/liter; resistant, ≥128 mg/liter. According to NCCLS guideline M31-A2, MIC breakpoints for florfenicol are as follows: sensitive, ≤2 mg/liter; resistant, ≥8 mg/liter.