Ceftiofur use in animal agriculture has been disputed due to the concern over the impact it may be having on the spread of resistance genes among foodborne pathogens. Several attempts to restrict the extra label use of ceftiofur have resulted in failure until the recent FDA ban. No study has been performed to see what impact ceftiofur removal would have on the reduction of third generation cephalosporin resistance mediated by the ¿¿-lactamase gene, blaCMY-2, among Salmonella enterica and Escherichia coli organisms.
The purpose of our study was to establish a baseline prevalence of third generation cephalosporin resistance among commensal E. coli organisms as well as the prevalence of Salmonella enterica among livestock populations and their represented meat products. Following the baseline establishment, ceftiofur use was discontinued to simulate a ban on the drug use, and the organisms of interest were monitored to determine the impact on the resistance genes among the enteric microflora. Monthly fecal samples were taking from select groups of livestock, and weekly ground beef and pork samples were collected.
At the conclusion of the study, the removal of ceftiofur did not impede our ability to culture third generation cephalosporin resistant E. coli organisms from the studied livestock populations. With regards to the fresh ground meat products, organisms
phenotypically resistant to third generation cephalosporins infrequently contaminate these products.¿¿¿