Outer Membrane Proteins of Pseudomonas aeruginosa. Their Role in Antibiotic Susceptibility

摘要

Experiments were done to measure the uptake of gentamicin (Gen)and dihydrostreptomycin (Sm) by Pseudomonas aeruginosa. Emphasis was placed on the study of: (a) the initial adsorption of Gen and Sm by the outer membrane (OM); and (b) the role played by various ions on their adsorption and uptake. When the Millipore filtration technique was used to measure adsorption and uptake, the amount of initial apparent adsorption that was detected was dependent on how the filters bearing the cells were washed, values being greatest when the cells were washed with water and at least when washed with solutions of salt. The apparent amount of antibiotic taken into the cells was also heavily dependent upon the lnature of the wash solutions. Equilibrium dialysis experiments showed that Gen and Sm were strongly adsorbed by isolated OM of P. aeruginosa and that ions such as Mg2+ prevented this adsorption. Pseudomonas aeruginosa PAO carrying the resistance plasmid RPI (R(+) strain) was studied with respect to tetracycline uptake and to the protein profile of the outer membrane (OM). The R(+) strain was compared to the parent strain lackling the plasmid (R(-) strain).