%0 Journal Article %A Gillespie, M. T. %A May, J. W. %A Skurray, R. A. %T Antibiotic Resistance in Staphylococcus Aureus Isolated at an Australian Hospital between 1946 and 1981 %D 1985 %J Journal of Medical Microbiology, %V 19 %N 2 %P 137-147 %@ 1473-5644 %R https://doi.org/10.1099/00222615-19-2-137 %I Microbiology Society, %X Summary 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) × 106 mol. wt, and that tetracycline resistance was encoded on a plasmid of 2·8 × 106 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 × 106 mol. wt plasmid which also encoded resistance to quaternary ammonium compounds. %U https://www.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-19-2-137