Table 2.
Prevalence of resistance to 13 antimicrobial agents. (A) Among E. coli isolates from dairy and beef cattle; results from the mixed logit model; (B) Among animals with resistant E. coli; results from the logistic model and tests of independence.
| (A) | ||||
| Antimicrobial Agent | Number (%) of E. coli Isolates | OR (95% CI) a | ||
| Cattle Barn n = 147 | Cattle Pasture n = 118 | |||
| Ampicillin | 31 (21,1) | 8 (6,8) | 0.21 (0.07–0.625) * | |
| Cefuroxime | 39 (26,5) | 14 (11,9) | 0.34 (0.157–0.733) * | |
| Ceftazidim | 11 (7.5) | 1 (0.8) | 0.12 (0.013–0.831) * | |
| Streptomycin | 30 (20,4) | 14 (11,9) | 0.35 (0.123–1.020) | |
| Gentamicin | 17 (11,6) | 7 (5,9) | 0.44 (0.148–1.330) | |
| Neomycin | 75 (51) | 29 (24,6) | 0.24 (0.116–0.51) * | |
| Tetracycline | 35 (23,8) | 13 (11) | 0.31 (0.103–0.938) * | |
| Doxycycline | 37 (25,2) | 16 (13,6) | 0.44 (0.184–1.027) | |
| Sulphamethoxazole | 19 (12,9) | 6 (5,1) | 0.36 (0.139–0.935) * | |
| Trimethoprim | 5 (3,4) | 6 (5,1) | 1.51 (0.441–5.190) | |
| Chloramphenicol | 8 (5,4) | 11 (9,3) | 1.79 (0.694–4.600) | |
| Nalidixic acid | 11 (7,5) | 11 (9.3) | 1.27 (0.531–3.044) | |
| Norfloxacin | 1 (0.7) | 3 (2.5) | 3.56 (0.251–50.652) | |
| Antimicrobial Susceptibility Characteristic | ||||
| R (“1”) | 121 (82.3) | 69 (58.5) | 0.28 (0.143–0.536) * | |
| S (“0”) | 26 (17.7) | 49 (41.5) | ||
| MDR (“1”) | 25 (17) | 10 (8.5) | 0.39 (0.147–1.018) | |
| NMDR (“0”) | 122 (83) | 108 (91.5) | ||
| R—resistant to at least one agent; S—susceptible; MDR—multidrug-resistant; NMDR—nonmultidrug-resistant; a reference category—cattle barn; * statistically significant. | ||||
| (B) | ||||
| Antimicrobial Agent | Number (%) of Animals with Resistant E. coli | OR (95% CI) a | Test of Independence p-value | |
| Cattle Barn n = 50 | Cattle Pasture n = 42 | |||
| Ampicillin | 21 (42) | 6 (14.3) | 0.23 (0.0821–0.645) * | 0.007 * |
| Cefuroxime | 24 (48) | 12 (28.6) | 0.43 ( 0.182–1.034) | 0.092 |
| Ceftazidim | 10 (20) | 1 (2.4) | 0.09 (0.012–0.797) * | 0.010 * |
| Streptomycin | 22 (44) | 9 (21.4) | 0.35 (0.138–0.875) * | 0.039 * |
| Gentamicin | 13 (26) | 6 (14.3) | 0.47 (0.163–1.384) | 0.261 |
| Neomycin | 38 (76) | 17 (40.5) | 0.21 (0.088–0.525) * | 0.001 * |
| Tetracycline | 20 (40) | 10 (23.8) | 0.47 (0.189–1.162) | 0.153 |
| Doxycycline | 23 (46) | 13 (31) | 0.53 (0.223–1.242) | 0.208 |
| Sulphamethoxazole | 17 (34) | 6 (14.3) | 0.32 (0.114–0.919) * | 0.033 * |
| Trimethoprim | 5 (10) | 6 (14.3) | 1.50 (0.423–5.315) | 0.540 |
| Chloramphenicol | 8 (16) | 9 (21.4) | 1.43 (0.498–4.116) | 0.690 |
| Nalidixic acid | 10 (20) | 9 (21.4) | 1.09 (0.397–3.000) | 1 |
| Norfloxacin | 1 (2) | 2 (4.8) | 2.45 (0.214–28.008) | 0.590 |
| a reference category—cattle barn; * statistically significant. | ||||