TABLE 1.
Distribution of integrons across farms and association with antibiotic resistance
| Integron group | Total no. of isolates | Farm(s) | No. (%) of isolates with resistance toa:
|
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Amox | Amp | Cef | Cm | Gen | Kan | St | Su | Tet | Spc | |||
| No Integrons | 392 | All | 2 (0.5) | 4 (1.0) | 3 (0.7) | 58 (14.8) | 0 | 21 (5.4) | 33 (8.4) | 78 (19.9) | 120 (30.6) | 64 (16.3) |
| 164 | D | 0 | 3 (1.8) | 0 | 4 (2.4) | 0 | 18 (11.0) | 28 (17.1) | 16 (9.8) | 52 (31.7) | 7 (4.3) | |
| 189 | K | 2 (1.1) | 1 (0.5) | 2 (1.1) | 54 (28.6) | 0 | 3 (1.6) | 5 (2.7) | 57 (30.2) | 66 (34.9) | 57 (30.2) | |
| 39 | R | 0 | 0 | 1 (2.6) | 0 | 0 | 0 | 0 | 5 (12.8) | 2 (5.1) | 0 | |
| 0 | S | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 1,000 bp | 285 | All | 0 | 1 (0.4) | 0 | 2 (0.7) | 11 (3.9) | 0 | 268 (94.0) | 285 (100) | 270 (94.7) | 285 (100) |
| 142 | D | 0 | 1 (0.7) | 0 | 2 (1.4) | 11 (7.8) | 0 | 142 (100) | 142 (100) | 127 (89.4) | 142 (100) | |
| 25 | K | 0 | 0 | 0 | 0 | 0 | 0 | 20 (80) | 25 (100) | 25 (100) | 25 (100) | |
| 118 | S | 0 | 0 | 0 | 0 | 0 | 0 | 106 (90.0) | 118 (100) | 118 (100) | 118 (100) | |
| 1,000 + 1,200 bp | 41 | All | 0 | 41 (100) | 0 | 41 (100) | 0 | 0 | 41 (100) | 41 (100) | 41 (100) | 41 (100) |
| 40 | D | 0 | 40 (100) | 0 | 40 (100) | 0 | 0 | 40 (100) | 40 (100) | 40 (100) | 40 (100) | |
| 1 | K | 0 | 1 (100) | 0 | 1 (100) | 0 | 0 | 1 (100) | 1 (100) | 1 (100) | 1 (100) | |
| 1,600 bp | 12 | All | 0 | 0 | 0 | 0 | 11 (91.7) | 8 (66.7) | 12 (100) | 12 (100) | 12 (100) | 12 (100) |
| 12 | D | 0 | 0 | 0 | 0 | 11 (91.7) | 8 (66.7) | 12 (100) | 12 (100) | 12 (100) | 12 (100) | |
| Total | 730 | All | 2 (0.2) | 46 (6.3) | 3 (0.4) | 101 (13.8) | 22 (3.0) | 29 (4.0) | 354 (48.5) | 416 (57.0) | 443 (60.7) | 402 (55.1) |
For table rows with data for all farms, phi coefficients for resistances to amoxicillin, ampicillin, cefoxitin, chloramphenicol, gentamicin, kanamycin, streptomycin, sulfisoxazole, tetracycline, and spectinomycin were 0.05, −0.23, 0.06, 0.03, −0.19, 0.8, −0.86, −0.81, −0.66, and −0.84, respectively, for the no-integron group; −0.04, −0.20, −0.05, −0.30, −0.04, −0.16, 0.73, 0.70, 0.56, and 0.73 for the 1,000-bp group; −0.01, 0.94, −0.02, 0.61, −0.04, −0.05, 0.25, 0.21, 0.20, and 0.22 for the 1,000- and 1,200-bp group; and −0.01, −0.03, −0.01, −0.05, 0.67, 0.42, 0.13, 0.11, 0.10 (statistical significance at an α of 0.10), and 0.12 for the 1,600-bp group, with statistical significance at an a of 0.001 unless otherwise indicated. Amox, amoxicillin; Amp, ampicillin; Cef, cefoxitin; Cm, chloramphenicol; Gen, gentamicin; Kan, kanamycin; St, streptomycin; Su, sulfisoxazole; Tet, tetracycline; Spc, spectinomycin.