In-vitro interactions of DX-8739, a new carbapenem, meropenem and imipenem with amikacin against multiresistant Pseudomonas aeruginosa

In order to investigate the antimicrobial interactions against multiresistant Pseudomonas aeruginosa, thirty-seven strains resistant to antimicrobial agents of five different chemical classes were exposed in vitro to the combination of three carbapenems, DX-8739, a novel DHP-I stable analogue, meropenem and imipenem with amikacin. The tested combinations expressed an enhanced killing activity against 38-46% of strains and an additive effect against 5-13%. These effects were the same whether the applied carbapenem was DX-8739, meropenem or imipenem: they were also independent of the MIC of any antimicrobial.