TABLE 1.

Resistance mechanisms, antibiotic resistance genes, and gene localization.

Chemical class	Target	Action	Genes	Gene localization	Reference(s)
Sulfonamides*	Folate synthesis	Bacteriostatic	sulI, sulII	P, T	Xu et al., 2018
β-Lactams	Cell-wall synthesis	Bactericidal	ampC, blaTEM, qnrS, tetW	P,C	Ferro et al., 2017; Pandey and Cascella, 2020
Amphenicols	Protein synthesis	Bacteriostatic Bactericidal	fexA, cat, cmlA, floR, cfr, fex	P, T, C	Rahal and Simberkoff, 1979; Kehrenberg and Schwarz, 2006; He et al., 2016
Aminoglycosides	Protein synthesis	Bactericidal	rmtA, rmtB, armA, gar	P
Tetracyclines	Protein synthesis	Bacteriostatic Bactericidal	tet*	P, T	Rahal and Simberkoff, 1979; Roberts, 2005
Macrolides	Protein synthesis	Bacteriostatic	erm*, carA, ole*, smrB, tlrC, vgaA, vgaB, lmrA, mefA, msr*, lsaA, lsaB, ereA, ereB, vgbA, vgbB, inuA, inuB, vat*, mph*	P, T	Kanfer et al., 1998; Roberts, 2005
Glycopeptides	Cell-wall synthesis	Bactericidal	van*	P	Binda et al., 2014; Lebreton and Cattoir, 2019
Oxazolidinones	Protein synthesis	Bacteriostatic	optrA, cfr	P, C	Diekema and Jones, 2001; Wang et al., 2015
Ansamycins	RNA synthesis	Bactericidal	rpoB	P	Floss and Yu, 2005
Quinolones	DNA synthesis	Bactericidal	qnr	P	Heeb et al., 2011; Hernández et al., 2011
Streptogramins	Protein synthesis	Bactericidal	erm*, carA, ole*, smrB, tlrC, vgaA, vgaB, lmrA, mefA, msr*, lsaA, lsaB, ereA, ereB, vgbA, vgbB, inuA, inuB, vat*, mph*	P, T	Roberts, 2005
Lipopeptides	Protein synthesis	Bactericidal	mprF, yycG, rpoB, rpoC, cls2, pgsA, agrA, prs, pnpA	P, C	Montero et al., 2008; Gómez Casanova et al., 2017
Lincosamides	Protein synthesis	Bacteriostatic	erm*, carA, ole*, smrB, tlrC, vgaA, vgaB, lmrA, mefA, msr*, lsaA, lsaB, ereA, ereB, vgbA, vgbB, inuA, inuB, vat*, mph*	P, T	Tenson et al., 2003; Roberts, 2005
Phenicols	Protein synthesis	Bacteriostatic Bactericidal	fexA, cat, cmlA, floR, cfr, fex	P, T, C	Kehrenberg and Schwarz, 2006; He et al., 2016
Pyrimidines	DNA synthesis	Bactericidal	dfrK, dfrD, dhfrI, dhfrX	P	Sundstrom and Skold, 1990; Parsons et al., 1991; Charpentier and Courvalin, 1997; Petersen et al., 2000; Masters et al., 2003; Kadlec and Schwarz, 2009
Sulfonamides	DNA Synthesis	Bactericidal	sul(1-4)	P, T	Connor, 1998; Razavi et al., 2017
Rifamycins	RNA Synthesis	Bactericidal	rpoB	P	Floss and Yu, 2005
Lipopeptides	Protein Synthesis	Bactericidal	mprF, yycG, rpoB, rpoC, cls2, pgsA, agrA, prs, pnpA, pmrHFIJKLM, pagP, phoP	P, C	Thorne and Alder, 2002; Montero et al., 2008; Gómez Casanova et al., 2017
Cationic peptides	DNA synthesis, RNA synthesis, Protein synthesis, Cell-wall synthesis	Bactericidal	pmrHFIJKLM, pagP, phoP	C	Devine and Hancock, 2002; Hale and Hancock, 2007

P, plasmid; C, chromosome; T, transposon; *Tet gene family, *Erm gene family, *cat gene family, *fex gene family, *ole gene family, *msr gene family, *vat gene family, *mph gene family, *Van gene family.