Épidémiologie de la résistance aux β-lactamines chez Pseudomonas aeruginosa

The opportunistic pathogen Pseudomonas aeruginosa is intrinsically resistant to many antibiotics. The low permeability of its outer membrane, the production of an active efflux system called MexAB-OprM, as well as inducible expression of a large-spectrum β-lactamase, AmpC, contribute to the relatively high resistance of this microorganism to β-lactams. Acquisition of higher levels of resistance to the most active molecules frequently involves mutations resulting in overexpression of AmpC, overproduction of one or more efflux pumps simultaneously or loss of specific porin OprD, the route of entry of carbapenems into the bacterium. These mechanisms coexist with production of transferable β-lactamases (penicillinases, extended-spectrum β-lactamases, carbapenemases) in epidemic, multidrug resistant clones.