confers_resistance_to_antibiotic confers_resistance_to_drug_class macrolide antibiotic fluoroquinolone antibiotic cephalosporin tetracycline resistance-nodulation-cell division (RND) antibiotic efflux pump confers_resistance_to_antibiotic confers_resistance_to_drug_class penicillin beta-lactam novobiocin trimethoprim chloramphenicol MexCD-OprJ MexCD-OprJ is a multidrug efflux protein expressed in the Gram-negative Pseudomonas aeruginosa. MexC is the membrane fusion protein; MexD is the inner membrane transporter; and OprJ is the outer membrane channel. MexAB-OprM is associated with resistance to fluoroquinolones, chloramphenicol, and macrolides. MexCD-OprJ is typically quiescent in wild-type cells, with expression following mutation of the nfxB gene that is divergently transcribed from the mexCD-oprJ operon and encodes a repressor of mexCD-oprJ expression. Expression of mexCD–oprJ is controlled by a single known regulator, the NfxB repressor encoded by the nfxB gene, which is transcribed divergently from the efflux genes. antibiotic_resistance ARO:3000797