[The new penicillins]

During recent years, new antibacterial beta-lactams have been identified. The association of beta-lactams and beta-lactamase inhibitors (clavulanic acid or sulbactam) represent a new therapeutic approach. The other drugs are classified into ureodopenicillins (mezlocillin, azlocillin, piperacillin), amidinopenicillins (mecillinam, pivmecillinam), monobactam (aztreonam) and penems (imipenem). Three mechanisms are involved in the bacterial resistance to these beta-lactams: inability to cross the bacterial membrane, inactivation of the antibiotic by a beta-lactamase, modification of the number of porines. The tolerance to these new products is good but they present a high risk for selection of resistant bacteria. These antibiotics markedly improve the treatment of beta-lactamase producing bacterial infections, particularly related to Pseudomonas aeruginosa.