Table 3. Results of susceptibility testing of Pseudomonas aeruginosa (n = 53 isolates) of each antibiotic used.
| Disk content (μg) | Zone diameter breakpoint (mm) |
Susceptiblea | Resistanta | ||||
|---|---|---|---|---|---|---|---|
| S ≥ | R < | N. (%) | Inhibition zone Ø (average ± SD) |
N. (%) | Inhibition zone Ø (average ± SD) |
||
| Penicillins | |||||||
| Piperacillin | 30 | 18 | 18 | 52 (98.11) | 24.6 ± 2.13 | 1 (1.88) | 14 ± 1.00 |
| Piperacillin+Tazobactam | 30–6 | 18 | 18 | 53 (100) | 25.8 ± 1.65 | 0 | - |
| Ticarcillin + Clavulanate | 75–10 | 18 | 18 | 51 (96.22) | 25.8 ± 2.17 | 2 (3.77) | 12.8 ± 2.54 |
| Ticarcillin | 75 | 18 | 18 | 53 (100) | 24.8 ± 3.46 | 0 | - |
| Cephalosporins | |||||||
| Cefepime | 30 | 19 | 19 | 53 (100) | 28.0 ± 2.35 | 0 | - |
| Ceftazidime | 10 | 16 | 16 | 53 (100) | 25.2 ± 2.71 | 0 | - |
| Carbapenems | |||||||
| Doripenem | 10 | 25 | 22 | 53 (100) | 35.2 ± 4.52 | 0 | - |
| Imipenem | 10 | 20 | 17 | 48 (90.56) | 29.6 ± 2.02 | 5 (9.43) | 13.2 ± 1.40 |
| Meropenem | 10 | 24 | 18 | 53 (100) | 34.7 ± 6.15 | 0 | - |
| Monobactams | |||||||
| Aztreonam | 30 | 50 | 16 | 53 (100) | 29.5 ± 2.31 | 0 | - |
| Fluoroquinolones | |||||||
| Ciprofloxacin | 5 | 25 | 22 | 53 (100) | 36.6 ± 2.96 | 0 | - |
| Levofloxacin | 5 | 20 | 17 | 53 (100) | 30.0 ± 2.49 | 0 | - |
| Aminoglycosides | |||||||
| Amikacin | 30 | 18 | 15 | 53 (100) | 23.3 ± 2.40 | 0 | - |
| Gentamicin | 10 | 15 | 15 | 53 (100) | 18.6 ± 2.17 | 0 | - |
| Tobramycin | 10 | 16 | 16 | 53 (100) | 24.7 ± 1.95 | 0 | - |
| Netilmicin | 10 | 12 | 12 | 53 (100) | 15.2 ± 2.59 | 0 | - |
aData of susceptible (S) or resistant (R) isolates according to EUCAST clinical breakpoint (www.eucast.org). Average of three experiments. Isolates with intermediate susceptibility are included into the “susceptible” category.