Chemical class | Antibiotic | Disk symbol | Disk content | Resistant | Intermediate | Susceptible |
Aminoglycosides | Gentamicin | GM | 10 µg | <18 mm S. aureus <22 mm CoNS | - | ≥18 mm S. aureus ≥22 mm CoNS |
β-lactams | Ampicillin | AP | 25 μg | <18 mm | - | ≥18 mm |
Cephalosporins (also a β-lactam) | Cefoxitin | FOX | 30 µg | <22 mm | - | ≥22 mm |
Fluoroquinolones | Ciprofloxacin | CIP | 5 µg | <20 mm | - | ≥20 mm |
Macrolides | Erythromycin | E | 15 µg | <18 mm | 18 - 20 mm | ≥21 mm |
Tetracyclines | Tetracycline | T | 30 µg | <19 mm | 19 - 21 mm | ≥22 mm |
Other | Rifampicin | RP | 5 µg | <23 mm | 23 - 25 mm | ≥26 mm |