Synergy between efflux pump CmeABC and modifications in ribosomal proteins L4 and L22 in conferring macrolide resistance in Campylobacter jejuni and Campylobacter coli

Macrolide-resistant mutants of Campylobacter jejuni and Campylobacter coli were selected in vitro using erythromycin and tylosin. These mutants exhibited modifications in the ribosomal proteins L4 (G74D) and L22 (insertions at position 86 or 98). A synergy between the CmeABC efflux pump and these modifications in conferring macrolide resistance was observed.