Table 4.
Prevalence of plasmid-mediated quinolone resistance (PMQR) and quinolone-resistance determining region (QRDR) mutations among Salmonella (enrofloxacin (ENR), minimum inhibitory concentrations (MIC) ≥ 0.25) isolated from hatcheries and their upstream breeder farms.
| Patterns | ENR MIC (µg/mL) | PMQR | QRDR Mutations | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| gyrA | parC | No. of Isolates | ||||||||
| Ser-83-Tyr | Ser-83-Phe | Ser-87-Gly | Tyr-57-Ser | Tyr-57-Thy | Hatchery | Breeder Farm | Total | |||
| P1 | 0.25−0.50 | □ | □ | □ | ■ | ■ | □ | 15 | 3 | 18 |
| P2 | 0.25−0.50 | □ | □ | ■ | □ | □ | ■ | 9 | 1 | 10 |
| P3 | 0.25−0.50 | □ | □ | ■ | □ | ■ | □ | 8 | 0 | 8 |
| P4 | 0.25 | □ | ■ | □ | □ | ■ | □ | 1 | 0 | 1 |
| P5 | 0.50 | □ | □ | □ | □ | ■ | □ | 0 | 1 | 1 |
| n, % | 0 | 1 (2.6) | 18 (47.4) | 18 (47.4) | 37 (97.4) | 1 (2.6) | 33 | 5 | 38 | |
n, indicates the number of isolates; % indicates the percentage; ■/□, indicate the presence/absence, respectively, of designated gene and mutation in each Salmonella isolate tested.