Summary Multidrug efflux pumps are ancient elements encoded in every genome, from bacteria to humans. In bacteria, in addition to antibiotics, efflux pumps extrude a wide range of substrates, including quorum sensing signals, bacterial metabolites, or plant‐produced compounds. This indicates that their original functions may differ from their recently acquired role in the extrusion of antibiotics during human infection. Concer...

Summary Multidrug (MDR) efflux pumps are ancient and conserved molecular machineries with relevant roles in different aspects of the bacterial physiology, besides antibiotic resistance. In the case of the environmental opportunistic pathogen Pseudomonas aeruginosa , it has been shown that overexpression of different efflux pumps is linked to the impairment of the quorum sensing (QS) response. Nevertheless, the causes of such i...