Characterization of outer membrane efflux proteins OpmE, OpmD and OpmB of Pseudomonas aeruginosa: molecular cloning and development of specific antisera.

The third genes, opmE, opmD and opmB, of multidrug efflux operons deduced from the Pseudomonas aeruginosa PAO1 genome data were cloned by polymerase chain reaction. The opmB gene product showed functional cooperation with inner membrane-associated components, MexAB, MexCD and MexXY, of the previously characterized multidrug efflux systems responsible for resistance to antimicrobial agents and extrusion of ethidium. The opmE and opmD gene products did not show functional cooperation. Immunoblots using a specific rabbit antiserum demonstrated, through exponential to stationary phases, constant expression of opmB and growth phase-dependent expression of opmD.