animals Article Effects of Zinc and Menthol-Based Diets on Co-Selection of Antibiotic Resistance among E. coli and Enterococcus spp. in Beef Cattle Sarah A. Murray 1, Raghavendra G. Amachawadi 2 , Keri N. Norman 3 , Sara D. Lawhon 1, Tiruvoor G. Nagaraja 4 , James S. Drouillard 5 and Harvey M. Scott 1,* 1 Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843, USA;
[email protected] (S.A.M.);
[email protected] (S.D.L.) 2 Department of Clinical Sciences, Kansas State University, Manhattan, KS 66506, USA;
[email protected] 3 Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843, USA;
[email protected] 4 Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506, USA;
[email protected] 5 Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS 66506, USA;
[email protected] * Correspondence:
[email protected]; Tel.: +1-(979)-847-6197 Simple Summary: As antibiotic resistance increases globally, alternatives to antibiotics are increas- ingly being investigated as growth promoters, as well as preventive and therapeutic agents, partic- ularly in agriculture. Equally important is the need for investigation into the effects of antibiotic Citation: Murray, S.A.; Amachawadi, alternatives on antibiotic resistance and particularly their risk for co-selection. In this study, we R.G.; Norman, K.N.; Lawhon, S.D.; explored the prevalence of antibiotic-resistant Escherichia coli and Enterococcus spp. in cattle fed zinc, Nagaraja, T.G.; Drouillard, J.S.; Scott, menthol or a combination of the two.