Antibiotic resistance in Staphylococcus aureus isolated at an Australian hospital between 1946 and 1981

J Med Microbiol. 1985 Apr;19(2):137-47. doi: 10.1099/00222615-19-2-137.


A total of 517 strains of Staphylococcus aureus isolated at a hospital in Melbourne, Australia between 1946 and 1981 was examined for resistance to a range of antimicrobial agents and for the presence of plasmid DNA. The use of mixed-culture transfer and restriction endonuclease analysis showed that the determinants for resistance to penicillin and to the heavy metals were carried by several related plasmids of (15-23) X 10(6) mol. wt, and that tetracycline resistance was encoded on a plasmid of 2.8 X 10(6) mol. wt in strains isolated before 1970. These phenotypes were chromosomally encoded in the majority of strains isolated thereafter. Resistance to chloramphenicol throughout the study period was plasmid-mediated. Of five aminoglycoside-resistance phenotypes, one was plasmid-mediated and three were chromosomally encoded. The remaining phenotype, specifying low-level gentamicin resistance, was found to be located on the chromosome of early isolates, but in later strains was borne by an 18 X 10(6) mol. wt plasmid which also encoded resistance to quaternary ammonium compounds.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminoglycosides / pharmacology
  • Anti-Bacterial Agents / pharmacology*
  • Australia
  • Bacteriophage Typing
  • Chloramphenicol / pharmacology
  • Chromosomes, Bacterial
  • Erythromycin / pharmacology
  • Gentamicins / pharmacology
  • Metals / pharmacology
  • Penicillin Resistance
  • Penicillins / pharmacology
  • Phenotype
  • R Factors*
  • Staphylococcus aureus / classification
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / isolation & purification
  • Tetracycline / pharmacology
  • Time Factors


  • Aminoglycosides
  • Anti-Bacterial Agents
  • Gentamicins
  • Metals
  • Penicillins
  • Erythromycin
  • Chloramphenicol
  • Tetracycline