An efflux pump is involved in secretion of newly synthesized siderophore by Pseudomonas aeruginosa.

Pseudomonas aeruginosa secretes the fluorescent siderophore, pyoverdine (PVD), to enable iron acquisition. Epifluorescence microscopy and cellular fractionation were used to investigate the role of an efflux pump, PvdRT-OpmQ, in PVD secretion. Bacteria lacking this efflux pump accumulated PVD, or a fluorescent precursor, in the periplasm, due to their inability to efficiently secrete into the media newly synthesized PVD. PvdRT-OpmQ is only the second system identified for secretion of newly synthesized siderophores by Gram negative bacteria.