Ninety-six penicillinase-producing strains of , all members of the phage-groups I and III, were examined for sensitivity to mercury, cadmium and arsenate.

Strains resistant to mercury, arsenate and cadmium were nearly always multiple-antibiotic resistant and produced large amounts of A-type penicillinase, much of it extracellular. They included representatives of a few widespread types of “hospital” staphylococci.

Other strains, that were sensitive to mercury but resistant to arsenate and cadmium appeared, though less frequently, to occur endemically in hospitals; they were generally sensitive to antibiotics other than penicillin and although they produced variable amounts of penicillinase, much of it was extracellular. Their penicillinase was either of the A-type or the C-type; in strains with A-type penicillinase the determinants for resistance to arsenate and cadmium appeared to be located on the penicillinase plasmid, but in strains with C-type penicillinase they appeared to be chromosomal. Penicillin-negative variants appeared relatively frequently in all but one of the cultures, suggesting that the genetic determinant for penicillinase production was on a plasmid; in one culture, however, there was evidence that it was chromosomal. Resistance to other antibiotics was not genetically linked with penicillinase production.


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