[Antibiotic extrusion and multidrug resistance].

Many bacteria evolved to have machineries that extrude noxious compounds across the cell membranes. Extrusion of such compounds through membranes of gram-negative bacteria is a complex, since the compounds need to cross two membranes. Typically, Pseudomonas aeruginosa and Escherichia coli produce power-operated antibiotic extrusion pumps and the exit membrane channel located in the inner and the outer membranes, respectively. The membrane fusion protein anchoring in the inner membrane and largely protruding the periplasmic space connects these two membrane proteins to facilitate extrusion of antibiotics.