Table 1.
Antibiotic resistance of Salmonella isolates recovered from retail raw chickens in different months.
| Antibiotic | Concentration range (μg/mL) | Total no. (%) | % Resistance to individual antibiotics |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2011 |
2012 |
|||||||||||
| April (n = 83) | May (n = 94) | June (n = 13) | July (n = 76) | August (n = 32) | September (n = 47) | October (n = 4) | January (n = 3) | February (n = 4) | March (n = 50) | |||
| Trimethoprim/sulfamethoxazole | 0/0–8/152 | 333 (82.0) | 45.8d | 93.6b | 100a | 94.7b | 87.5b | 70.2c | 100a | 100a | 100a | 100a |
| Nalidixic acid | 0–64 | 292 (71.9) | 34.9c | 99a | 100a | 90.8b | 43.8c | 38.3c | 100a | 100a | 98.0a | |
| Tetracycline | 0–32 | 241 (59.4) | 57.8c | 86.2b | 38.5 | 82.9b | 56.3c | 36.2 | 100a | 75.0b | 4.0 | |
| Ampicillin | 0–64 | 219 (53.9) | 25.3 | 88.3b | 30.8 | 76.3c | 75.0c | 36.2 | 100a | 100a | 75.0c | 4.0 |
| Amoxicillin/clavulanic acid | 0/0–64/32 | 212 (52.2) | 25.3 | 86.2b | 38.5 | 69.7c | 71.9c | 34.0 | 100a | 100a | 100a | 4.0 |
| Chloramphenicol | 0–64 | 212 (52.2) | 21.7 | 89.4b | 15.4 | 68.4c | 43.8 | 72.3c | 100a | 75.0c | 2.0 | |
| Kanamycin | 0–128 | 158 (38.9) | 22.9 | 76.6a | 23.1 | 32.9 | 65.6a | 34.0 | 50.0b | |||
| Ceftiofur | 0–128 | 154 (37.9) | 20.5 | 69.1c | 14.5 | 18.8 | 17.0 | 100a | 33.3 | 25.0 | 82.0b | |
| Streptomycin | 0–64 | 136 (33.5) | 18.1c,d | 83b | 15.4d | 27.6c | 21.9c,d | 17.0c,d | 25.0c,d | 100a | 2.0 | |
| Gentamicin | 0–32 | 116 (28.6) | 19.3c | 41.5a,b | 7.7 | 32.9b | 53.1a | 34.0b | 25.0b,c | 2.0 | ||
| Ciprofloxacin | 0–16 | 90 (22.2) | 25.3b,c | 47.9a | 7.7 | 1.3 | 18.8c | 31.9b | 25.0b,c | |||
| Amikacin | 0–128 | 80 (19.7) | 15.7c | 26.6b,c | 13.2c | 53.1a | 29.8b | 2.0 | ||||
| Ceftriaxone | 0–128 | 73 (18.0) | 19.3a,b | 29.9a | 15.8b | 3.1 | 29.8a | 4.0 | ||||
| Cefoxitin | 0–64 | 70 (17.2) | 1.2 | 18.1d | 23.7c,d | 43.8b | 29.8c | 100a | 4.0 | |||
Values sharing the same superscript letter in each row are not significantly different (P > 0.05).