Table 5.
Ranking of the most common drug-resistant phenotypes among 1,423 Escherichia coli by farm record treatment (Tx) with enrofloxacin or ceftiofur
| Drug-resistant phenotypes1 | TX rank2 | NoTX rank2 | Tx, % (no.) | NoTx, % (no.) |
|---|---|---|---|---|
| Enrofloxacin (Tx, n = 152; NoTx, n = 1,238) | ||||
| AMP-FOX-CHL-STR-TET | 1 | 3 | 7.9 (12) | 4.4 (56) |
| AMP-TIO-CRO-CIP-NA-TET | 2 | 23 | 5.3 (8) | 1.4 (18) |
| AMP-FOX-NEO-STR-TET | 3 | 4 | 4.6 (7) | 4.2 (54) |
| CHL-STR-TET | 27 | 1 | 0.7 (2) | 5.7 (72) |
| TET | 43 | 2 | 0.7 (1) | 5.1 (65) |
| Pansusceptible | 15.8 (24) | 11.8 (150) | ||
| Ceftiofur (Tx, n = 144; NoTx, n = 1,279) | ||||
| AMP-FOX-TIO-CHL-NEO-STR-TET-COT | 1 | 23 | 14.5 (21) | 1.4 (18) |
| AMP-FOX-CHL-GEN-STR-TET | 2 | 24 | 13.2 (19) | 1.1 (15) |
| AMP-TIO-STR-TET-COT | 3 | 77 | 6.9 (10) | 0.2 (2) |
| CHL-STR-TET | None | 1 | 0 (0) | 5.8 (74) |
| TET | None | 2 | 0 (0) | 5.1 (66) |
| AMP-FOX-CHL-STR-TET | 6 | 3 | 4.1 (6) | 4.9 (62) |
| Pansusceptible | 0.3 (1) | 13.5 (173) | ||
1
AMP = ampicillin; FOX = cefoxitin; TIO = ceftiofur; CRO = ceftriaxone; CIP = ciprofloxacin; CHL = chloraphenicol; GEN = gentamicin; NA = nalidixic acid; NEO = neomycin; STR = streptomycin; COT = trimethoprim sulfamethoxazole; TET = tetracycline.
2
Ranking of drug-resistant phenotypes for isolates from a calf with a farm record of receiving at least one treatment with the referred drug (Tx) or from a calf with a farm record showing no treatment with the referred drug (NoTx).