Zaheer, Rahat; Cook, Shaun R.; Klima, Cassidy L.; Stanford, Kim; Alexander, Trevor; Topp, Edward; Read, Ron R.; McAllister, Tim A. (Canada)
Frontiers in Microbiology (2013)
This study investigated the effects of administering macrolides to beef cattle either systemically through a single subcutaneous injection (therapeutic) or continuously in-feed (subtherapeutic), on the prevalence and antimicrobial resistance of Mannheimia haemolytica and Enterococcus spp. isolated from the nasopharynx and faeces, respectively. Nasopharyngeal and faecal samples were collected weekly over 28 days from untreated beef steers and from steers injected once with tilmicosin or tulathromycin or continuously fed tylosin phosphate at dosages recommended by manufacturers.
Rectal faecal and nasopharyngeal swab samples were taken from all 40 animals on arrival (day 0) at the facility, and then weekly thereafter for 4 weeks. Enterococcus was isolated and erythromycin-resistant isolates were evaluated for the presence of the commonly found macrolide resistance determinants erm(A), erm(B), erm(C), erm(F), erm(T), erm(X), mef(A) using PCR.
AST Method: Disk Diffusion
Reference explicitly reports AST breakpoints: True
Reference reports using a MIC table: False
Is Excluded: True
| Country | Sub-Region | Sub-Region Detail |
|---|---|---|
| Canada | None | Alberta |
| Canada | Alberta (Province) | Lethbridge Research Centre |
| ID | Note | Resolution |
|---|
| Title | Host | Host | Production Stage | Description | ROs |
|---|---|---|---|---|---|
| Macrolide use | Cattle | Beef Steers | Feedlot | Use of macrolides in cattle; single SQ injection (Tilmicosin, Tulathromycin) or in-feed (Tylosin). Erythromycin-resistance determined by presence of genes erm(A), erm(B), erm©, erm(F), erm(T), erm(X), mef(A). | 1 |
| Macrolide use | Cattle | Beef Steers | Feedlot | Use of macrolides in cattle; single SQ injection (Tilmicosin, Tulathromycin) or in-feed (Tylosin). Erythromycin-resistance determined by presence of genes erm(A), erm(B), erm©, erm(F), erm(T), erm(X), mef(A). Control: No Antibiotics | 1 |
| Macrolide use | Cattle | Beef Steers | Feedlot | Use of macrolides in cattle; single SQ injection o (Tilmicosin, Tulathromycin) or in-feed (Tylosin). Erythromycin-resistance determined by presence of genes erm(A), erm(B), erm©, erm(F), erm(T), erm(X), mef(A). | 1 |