strain R1, originally isolated from a patient whose burns were treated with silver sulphadiazine, contained two large plasmids of 83 kb (pJT1) and 77 kb (pJT2), and was resistant to 1 mM AgNO. A silver-sensitive derivative, S1, cured of the 83-kb plasmid pJT1, was obtained by growth at 46°C. Studies with an Ag -specific ion electrode showed no significant differences in Ag binding by washed resting cell suspensions of strains R1 and S1, with and without glucose. However, transmission electronmicroscopy and energy dispersive X-ray analysis of whole cell mounts from actively growing cultures showed that the Ag-resistant strain did not accumulate Ag, whereas the sensitive strain contained dense silver particles. Both strains produced HS, detected by blackening of lead acetate paper above inoculated broth, and reducing substances (possibly HS) were detected only around R1 colonies when methylene blue was used as a indicator in LB agar, which may be a less sensitive assay. The mechanism of silver resistance is not known, but actively growing cells of R1 did not accumulate silver.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error