Table 3.

Antimicrobial resistance genes found in Escherichia coli isolated from U.S. food animals.

Antimicrobial class	Genes	References
Aminoglycosides	aac(3′), aac(6′), aadA, aadE, strA/B, aph	Ramirez and Tolmasky, 2010; Frye et al., 2011; Glenn et al., 2012
β-lactams	ampC, ampR, blaCMY−2, blaPSE−1, blaTEM−1	Li et al., 2007; Frye et al., 2011; Glenn et al., 2012
Chloramphenicol	cat1, cmlA, floR	Keyes et al., 2000; White et al., 2000; Bischoff et al., 2002; Frye et al., 2011; Glenn et al., 2012
Fluoroquinolones	Mutations in Quinolone Resistance Determining Regions (QRDR) of gyrA, gyrB, parC, parE	Hopkins et al., 2005
Folate pathway inhibitors	sul1, sul2, sul3, dfr	Graves et al., 2002; Ajiboye et al., 2009; Frye et al., 2011; Glenn et al., 2012
Tetracyclines	tet(A), tet(B), tet(C), tet(G), tet(M), and regulator tetR	Bryan et al., 2004; Frye et al., 2011; Glenn et al., 2012