TABLE 1.
Pattern of genetic determinants of enrofloxacin resistance in E. coli clinical isolates of swine origin
| MIC (μg/ml) | Pattern of genetic determinants (no. of isolates) | ST type(s) (no. of isolates) |
|---|---|---|
| >2 | gyrA(S83L) + gyrA(D87Y or D87N or D87G) + parC(S80I or S80R) ± other genetic determinantsa (49) | 744 (11), 100 (10), 224 (4), 410 (3), 10 (2), 457 (2), 617 (2), 4981 (2), 88 (1), 93 (1), 167 (1), 977 (1), 1585 (1), 2161 (1), 3901 (1) |
| 2 | gyrA(S83L) + parC(S80I or S80R) (23) | 100 (21), 58 (1), 90 (1) |
| qnrB19 (2) | 361 (1), 2496 (1) | |
| No genetic determinants (1) | 5926 (1) | |
| 1 | gyrA(S83L) + parC(S80I or S80R) (7) | 100 (6), 69 (1) |
| gyrA(S83L) only (1) | 6234 (1) | |
| gyrA(D87G) + qnrB2 (1) | 10 (1) | |
| aac(6′)-Ib-cr + qnrB2 (1) | 540 (1) | |
| Single PMQR (qnrB19, qnrS1, qnrS2, qnrB2, or qnrB77) (8) | 10 (4), 101 (1), 641 (1), 847 (1), 5759 (1) | |
| 0.25–0.5 | gyrA(S83L) ± aac(6′)-Ib-cr (6) | 6234 (2), 10 (1), 58 (1), 101 (1), 410 (1) |
| Single PMQR (qnrB19, qnrS1, qnrS2, qnrB2) (5) | 10 (3), 93 (1), 1112 (1) | |
| gyrA (D87G or D87Y) (3) | 10 (1), 88 (1), 641 (1) | |
| aac(6′)-Ib-cr + qnrB2 (1) | 641 (1) | |
| No genetic determinants (2) | 641 (1), 3057 (1) | |
| ≤0.125 | gyrA(S83L) (3) | 10 (1), 847 (1), unknown (1) |
| gyrA(D87Y) (1) | 90 (1) |
a
This genetic determinant might or might not be present in isolates with that particular MIC value. Other determinants were parC(A56T or E84G), parE(S458A or L416F), and single PMQR [aac(6′)-Ib-cr, qnrB77, or qnrB19].