Table 4.
Associations between antimicrobial exposure in pigs and resistance in C. coli by farm stagea
| Farm stageb | Antimicrobial use on farms |
Antimicrobial susceptibility testing |
Pc | OR | 95% CI | |||
|---|---|---|---|---|---|---|---|---|
| Antimicrobial | No. pigs exposed/total no. of pigs (%) | Antimicrobial testedd | No. of resistant pigs/no. of pigs exposed (%) | No. of resistant pigs/no. of pigs not exposed (%) | ||||
| Farrowing (n = 202) | ENR | 60/202 (29.7) | CIP | 5/60 (8.3) | 0/142 | <0.01* | NA | NA |
| NAL | 5/60 (8.3) | 0/142 | <0.01* | NA | NA | |||
| Nursery (n = 476) | LIN | 45/476 (9.5) | CLI | 1/45 (2.2) | 15/431 (3.5) | 0.65 | 0.6 | 0.1–4.9 |
| ENR | 45/476 (9.5) | CIP | 27/45 (60) | 78/431 (18.1) | <0.01 | 6.8 | 3.6–12.9 | |
| NAL | 27/45 (60) | 74/431 (17.2) | <0.01 | 7.2 | 3.8–13.8 | |||
| OTC | 386/476 (81.1) | TET | 348/386 (90.2) | 88/90 (97.8) | 0.01 | 0.2 | 0.05–0.9 | |
| CTC | 476/476 (100) | TET | 436/476 (91.6) | NA | NA | NA | NA | |
| TIA | 386/476 (81.1) | AZI | 76/386 (19.7) | 42/90 (46.7) | <0.01 | 0.3 | 0.2–0.5 | |
| ERY | 76/386 (19.7) | 42/90 (46.7) | <0.01 | 0.3 | 0.2–0.5 | |||
| Finishing (n = 421) | CTC | 369/421 (87.6) | TET | 341/369 (92.4) | 49/52 (94.2) | 0.63 | 0.7 | 0.2–2.5 |
| TIA | 369/421 (87.6) | AZI | 90/369 (24.4) | 24/52 (46.2) | <0.01 | 0.4 | 0.2–0.7 | |
| ERY | 89/369 (24.1) | 24/52 (46.2) | <0.01 | 0.4 | 0.2–0.7 | |||
a
Abbreviations: ENR, enrofloxacin; LIN, lincomycin; TIA, tiamulin; OTC, oxytetracycline; CTC, chlortetracycline; CIP, ciprofloxacin; NAL, nalidixic acid; CLI, clindamycin; TET, tetracycline; AZI, azithromycin; ERY, erythromycin. NA, not applicable.
b
n = the total number of pigs at the production stage.
c
Determined using the chi-square except as noted. *, Determined using the Fisher exact test.
d
These antimicrobials are included in the Campylobacter susceptibility testing panel.