Effect of silver on whole cells and spheroplasts of a silver resistant Pseudomonas aeruginosa.

Electron micrographs of a silver resistant strain of Pseudomonas aeruginosa grown in the presence of 50 micrograms/ml Ag+ indicate that the surviving cells are resistant at the level of the cytoplasmic membrane. Spheroplasts of the resistant strain were not lysed by 1 h contact with 8 micrograms/ml Ag+, but were 36% and 22% lysed by 1 h contact with 20 micrograms/ml chlorhexidine and 40 micrograms/ml polysorbate 80, respectively. Spheroplasts of a silver sensitive strain of P. aeruginosa were lysed by 22% on contact with 1 microgram/ml Ag+ for 1 h.