[Imipenem resistance in Pseudomonas aeruginosa]

Mutants of P. aeruginosa resistant to imipenem can be selected at high frequency in vitro. They remain susceptible to other beta-lactams. Strains resistant both against imipenem and other beta-lactams are, however, detectable in vitro and in vivo. Imipenem-resistant strains appeared in blood cultures and emergence of IMI-resistance during therapy has been observed. The activity of other beta-lactams against P. aeruginosa is antagonized in the presence of IMI, because of beta-lactamase induction by imipenem. In addition to the risk of emergence of IMI-resistance of P. aeruginosa during therapy, there is an increasing incidence of IMI-resistant strains already existing prior to therapy. In the treatment of infections caused by P. aeruginosa combination therapy including a non-beta-lactam antibiotic active against the pathogen is indicated.