Table 1.

Resistance genes found on mobile genetic elements in Gram-negative bacilli.

Resistance Gene	Antibiotic Class	Mobile Genetic Element	Mechanism of Resistance
blaCTX-M	β-lactams (Cephalosporins)	Plasmids, integrons	Extended-spectrum β-lactamase production
blaKPC	β-lactams (Carbapenems)	Plasmids, transposons	Carbapenemase production
blaNDM	β-lactams (Carbapenems)	Plasmids, integrons	Metallo-β-lactamase production
blaOXA-48	β-lactams (Carbapenems)	Plasmids, integrons	Carbapenemase production
blaVIM	β-lactams (Carbapenems)	Plasmids, integrons, transposons	Metallo-β-lactamase production
qnr	Fluoroquinolones	Plasmids	Plasmid-mediated quinolone resistance (PMQR)
mcr-1	Polymyxins (Colistin)	Plasmids	Phosphoethanolamine transferase production
tet(A)	Tetracyclines	Plasmids, transposons	Tetracycline efflux pump
dfrA	Trimethoprim	Plasmids, integrons	Dihydrofolate reductase alteration
armA	Aminoglycosides	Plasmids	Methyltransferase production (16S rRNA methylation)