In vitro antimicrobial activity of liposomal meropenem against Pseudomonas aeruginosa strains.

Author(s): Drulis-Kawa Z, Gubernator J, Dorotkiewicz-Jach A, Doroszkiewicz W, Kozubek A

Affiliation(s): Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland. kawa@microb.uni.wroc.pl

Publication date & source: 2006-06-06, Int J Pharm., 315(1-2):59-66. Epub 2006 Mar 6.

Publication type: Comparative Study; Research Support, Non-U.S. Gov't

Twelve lipid formulations of liposomal meropenem were tested on six drug-susceptible and two drug-resistant Pseudomonas aeruginosa strains to determine their antibacterial activity. Cationic liposomes, especially PC/DOPE/SA 4:4:2 and PC/DOTAP/Chol 5:2:3, were more effective than anionic ones against sensitive isolates as the MICs of those formulations were two to four times lower than those of the free drug. None of the studied liposomal forms of meropenem exhibited bactericidal activity against isolates, which are drug-resistant due to low permeability. Even Fluidosomes (liposomes made of DPPC/DMPG 18:1), which demonstrated fusion with P. aeruginosa membranes, showed 4-16 times higher MICs for sensitive and resistant strains than did the free meropenem.