Abstract
This paper reports that the efficiency of solute diffusion through the outer membrane of Pseudomonas maltophilia is roughly 3 to 5% of that of Escherichia coli. This is despite the fact that the outer membrane pore(s) is only a little smaller than that of E. coli. These results suggest that P. maltophilia has a low copy number of porin(s). The outer membrane of antibiotic resistant clinical isolates showed even less efficient permeability towards saccharides and antibiotics than the laboratory strains.