Table 1. Antibiotic resistance mechanisms of Campylobacter.

Antibiotic class	Resistance mechanisms
Aminoglycoside	Modification of the antibiotic by aminoglycoside-modifying enzymes (AphA, AadE, Sat) Contribution of efflux is not clear
Beta-Lactam	Enzymatic inactivation of the antibiotic by β-lactamase (penicillinase, OXA-61) Decreased membrane permeability of most anionic and MW > 360 kDa antibiotics due to MOMP Efflux through CmeABC and possibly others
Fluoroquinolone	Modification of the DNA gyrase target (Thr-86-Ile; also Asp-90-Asn, Ala-70-Thr) Efflux through CmeABC
Macrolide	Mutations in 23S rRNA Contribution of mutations in ribosomal proteins L4/L22 is likely minor Efflux through CmeABC and possibly others Decreased membrane permeability due to MOMP
Tetracycline	Modification of the target ribosomal A site by TetO binding Efflux through CmeABC and possibly others Contribution of decreased membrane permeability due to MOMP is not clear