TABLE 3.
Percent antibiotic resistance and MIC range of S. Kentucky, other Salmonella serotypes and ESBL-producing Salmonella isolates from poultry meat and faecal samples.
| Class and antibiotics (μg/disc) | E-test | Disk diffusion: No. of samples demonstrating resistance (percentage of isolates resistant) | |||
|---|---|---|---|---|---|
| MIC Range μg/mL | Salmonella Kentucky (n = 32)† | Other Salmonella serotypes (n = 40) | Salmonella ESBL-producers (n = 6) | Total (n = 78) | |
| Sulphonamides | |||||
| Sulfamethoxazole (300 μg) | NA | 32 (100) | 38 (95) | 6 (100) | 76 (97) |
| Trimethoprim/Sulphamethoxazole (1.25 μg/23.75 μg) | 0.094 – >32 | 23 (72) | 14 (35) | 3 (50) | 40 (51) |
| Tetracyclines | |||||
| Tetracycline (30 μg) | 2 – >256 | 31 (97) | 38(95) | 6(100) | 75(96) |
| Quinolones | |||||
| Naldixic acid (30 μg) | 4 – >256 | 30 (94) | 39 (98) | 6 (100) | 75 (96) |
| Penicillins | |||||
| Ampicillin (10 μg) | 24 – >256 | 31 (97) | 22 (55) | 6 (100) | 59 (76) |
| β-lactamases | |||||
| Ticarcillin/clavulanate (75/10 μg) | NA | 30 (94)‡ | 17 (43)‡ | 5 (83) | 52 (67) |
| Ampicillin/sulbactam (10/10 μg) | 3-256 | 11 (34) | 12 (30) | 2 (33) | 25 (32) |
| Phenicols | |||||
| Chloramphenicol (30 μg) | NA | 26 (81) | 16 (40) | 2 (33) | 44 (56) |
| Fluoroquinolones | |||||
| Ciprofloxacin (5 μg) | 0.19–12 | 31 (97)‡ | 1 (3)‡ | 4 (66) | 36 (46) |
| Aminoglycosides | |||||
| Streptomycin (10 μg) | 0.38–512 | 1 (3) | 21 (53) | 6 (100) | 28 (36) |
| Gentamicin (10 μg) | 0.38–24 | 9 (28) | 13 (33) | 3 (50) | 24 (31) |
| Amikacin (30 μg) | 1–2 | 1 (3) | 0 | 0 | 1 (1) |
| Monobactam | |||||
| Aztreonam (30 μg) | NA | 1 (3) | 0 | 6 (100) | 7 (9) |
| Cephems | |||||
| Cefotaxime (30 μg) | 24 – >256 | 1 (3) | 1 (3) | 6 (100) | 8 (10) |
| Ceftriaxone (30 μg) | 0.125 – >32 | 1 (3) | 0 | 4 (66) | 5 (6) |
| Ceftazidime (30 μg) | 0.38 – >256 | 1 (3) | 0 | 4 (66) | 5 (6) |
| Cefepime (30 μg) | 0.19–3 | 0 | 0 | 0 | 0 |
| Carbapenems | |||||
| Imipenem (10 μg) | 0.038-0.125 | 0 | 0 | 0 | 0 |
†, 2 of the 34 Salmonella Kentucky isolates were ESBL-producers and are included in the Salmonella ESBL producers column.
‡, Significant difference in resistance level found between S. Kentucky and other Salmonella serotypes were calculated at p < 0.01.
MIC, minimum inhibitory concentration; ESBL, extended-spectrum β-lactamases.