Beukers, Alicia G. and Zaheer, Rahat and Cook, Shaun R. and Stanford, Kim and Chaves, Alexandre V. and Ward, Michael P. and McAllister, Tim A. (Canada)
Frontiers in Microbiology (2015)
British crossbred steers (150 ± 20 kg) were randomly assigned to 10 pens (10 steers per pen) at the Lethbridge Research Centre feedlot (Lethbridge, Alberta, Canada). Steers were obtained from a single ranch (Deseret Ranches, Raymond, Alberta, Canada) and received no antibiotics prior to the beginning of the experiment. Five pens of cattle each were randomly assigned to one of two treatments: (i) control, no antibiotics (denoted CON); (ii) tylosin phosphate (Tylan R, Elanco Animal Health; treatment denoted T11) at 11 ppm in the diet. Tylosin was administered continuously for 197 days, starting on arrival at the feedlot and was withdrawn from the diet 28 days prior to slaughter.
The study occurred from November 2004 to July 2005. Rectal fecal samples were collected from each steer upon arrival at the feedlot and monthly thereafter until slaughter. Agar containing no antibiotics or onto BEA amended with erythromycin (8 μg/mL; BEAE), or tylosin (32 μg/mL; BEAT) to select for enterococci resistant to erythromycin or tylosin. Proportion of steers positive for macrolide resistant enterococci, CFU counts and the proportion of macrolide resistant enterococci in steers were estimated at all 9 sampling dates with enterococci isolates from 5 of these dates used for assessing antimicrobial susceptibility, identifying resistance determinants and PFGE profiles.
AST Method: Disk Diffusion
Reference explicitly reports AST breakpoints: True
Reference reports using a MIC table: Uncertain
Is Excluded: False
| Country | Sub-Region | Sub-Region Detail |
|---|---|---|
| Canada | Alberta (Province) | Lethbridge |
| Canada | Alberta (Province) | Lethbridge Research Centre feedlot |
| ID | Note | Resolution |
|---|
| Title | Host | Host | Production Stage | Description | ROs |
|---|---|---|---|---|---|
| Tylosin use | Cattle | Beef Steers | Feedlot | Control cattle (No antibiotics) and cattle fed Tylosin Phosphate (11ppm) fed contunuously for 197 days, withdrawn 28 days prior to slaughter (T11). Data are prevalence from erythromycin resistant media. | 1 |
| Tylosin use | Cattle | Beef Steers | Feedlot | Control cattle (No antibiotics) and cattle fed Tylosin Phosphate (11ppm) fed contunuously for 197 days, withdrawn 28 days prior to slaughter (T11). Data are prevalence from tylosin resistant media. | 1 |