Long-Term Effects of Single-Dose Cephalosporin or Macrolide Use on the Prevalence of AmpC and Extended-Spectrum β-Lactamase Producing <i>Escherichia coli</i> in the Feces of Beef C... oleh Gizem Levent, Ashlynn Schlochtermeier, Javier Vinasco, Jenny Jennings, John Richeson, Samuel E. Ives, Keri N. Norman, Sara D. Lawhon, Guy H. Loneragan, H. Morgan Scott