Antimicrobial class | Antimicrobial agent | Code | Dose | Zone diameter interpretive criteria | ||
---|---|---|---|---|---|---|
 |  |  |  | Sensitive | Intermediate | Resistance |
Cell envelope antibiotics | Â | Â | Â | |||
 Penicillins | Ampicillin | AMP | 10 μg | ≥17 | 14–16 | 13 |
Penicillin G | P | 10 unit | ≥29 | 21–28 | ≤20 | |
 Cephems | Cefotaxime | CTX | 30 μg | ≥26 | 19–24 | ≤18 |
Cefepime | FEP | 30 μg | ≥25 | 19–24 | ≤18 | |
Cephalothin | KF | 30 μg | ≥18 | 15–17 | ≤14 | |
Protein synthesis inhibitors | Â | Â | Â | |||
 Aminoglycosides | Gentamycin | CN | 10 μg | ≥15 | 12–14 | ≤11 |
Kanamycin | K | 30 μg | ≥18 | 14–17 | ≤13 | |
Streptomycin | S | 10 μg | ≥15 | 12–14 | ≤11 | |
 Tetracyclines | Tetracycline | TE | 30 μg | ≥ |  | ≤ |
Nucleic acid inhibitors | ||||||
 Quinolones | Ciprofloxacin | CIP | 5 μg | ≥21 | 16–20 | ≤15 |
 | Nalidixic acid | NA | 30 μg | ≥19 | 14–18 | ≤13 |
 DNA inhibitors | Nitrofurantoin | F | 300 μg | ≥17 | 15–16 | ≤14 |
 Potentiated sulfonamides | Sulfamethoxazole/trimethoprim | SXT | 1.25/23.75 μg | ≥16 | 11–15 | ≤10 |
Phenicol derivatives | ||||||
 Chloramphenicols | Chloramphenicol | C | 30 μg | ≥18 | 13–17 | ≤12 |
Transpeptidation/Translocation | ||||||
 Macrolides | Erythromycin | E | 15 μg | ≥18 | 14–17 | ≤13 |
Glycopeptide | ||||||
 Polypeptides | Vancomycin | VA | 30 μg | ≥12 | 10–11 | ≤9 |