Location: Meat Safety & Quality ResearchTitle: Antimicrobial use and resistance in United States beef production
Submitted to: American Chemistry Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 12/26/2018
Publication Date: N/A
Technical Abstract: Food-animals receive approximately 80% (by mass) of antimicrobials used in the United States (U.S.). Cattle account for about 43% of the medically important antimicrobials used in animals. This has raised concerns that antimicrobial use during cattle production contributes significantly to (colloquially, "drive") antimicrobial resistance (AMR), especially human infections resistant to "critically-important" antimicrobials. The U.S. Meat Animal Research Center (USMARC) has performed numerous studies to assess the impact of antimicrobial use in U.S. cattle production on AMR. First, levels of antimicrobial-resistant bacteria were similar among beef cattle production waste, swine production waste, and human municipal wastewater treatment plant (WWTP) effluent. Interestingly, significantly higher levels of beta-lactam and fluoroquinolone resistance genes were detected in human municipal WWTP effluent. Second, a 5-day in-feed chlortetracycline administration to cattle for the management of respiratory disease had minimal to no effect on AMR levels, especially long-term (> 27 days post treatment). Third, cecal contents obtained from 719 cattle during harvest harbored generally similar AMR levels between cattle produced with and without antibiotics. However, cattle raised without antibiotics typically grow slower, so they must be fed longer, resulting in the production of more manure, which may offset the AMR differences. Fourth, croplands amended with beef cattle manure contained generally similar AMR levels compared to croplands amended with inorganic fertilizer and no amendment control croplands. Fifth, ground beef from animals produced with and without antibiotics harbored generally similar AMR levels. In conclusion, typical antimicrobial use during U.S. cattle production does not broadly increase AMR in cattle production environments or in beef products. Arguably, these results indicate that the impact of antimicrobial use during U.S. cattle production on human AMR exposure are inconsequential.