%0 Journal Article %A Coleman, D. C. %A Pomeroy, H. %A Estridge, J. K. %A Keane, C. T. %A Cafferkey, M. T. %A Hone, R. %A Foster, T. J. %T Susceptibility to Antimicrobial Agents and Analysis of Plasmids in Gentamicin- and Methicillin-Resistant Staphylococcus Aureus From Dublin Hospitals %D 1985 %J Journal of Medical Microbiology, %V 20 %N 2 %P 157-167 %@ 1473-5644 %R https://doi.org/10.1099/00222615-20-2-157 %I Microbiology Society, %X Summary Methicillin- and gentamicin-resistant Staphylococcus aureus (MGRSA) strains isolated from Dublin Hospitals were classified into two groups (phenotypes). Phenotype-I strains expressed high level resistance to gentamicin and were susceptible to fusidic acid; strains resistant to tetracycline harboured a 3 x 106-mol. wt plasmid. Strains in phenotype II usually expressed low level resistance to gentamicin, were resistant to fusidic acid and often harboured a (22-24) x 106-mol. wt plasmid that specified resistance to ethidium bromide, tetracycline, kanamycin, neomycin and trimethoprim, or to combinations of these markers. A few phenotype-II strains expressed higher levels of resistance to gentamicin and other aminoglycosides. All MGRSA strains carried a 21 x 106-mol. wt plasmid conferring resistance to penicillin, ethidium bromide, cadmium and mercury. Gentamicin resistance was invariably chromosomal and all strains carried chromosomal resistance to methicillin, erythromycin, streptomycin and spectinomycin. Several methicillin-resistant S. aureus (MRSA) strains isolated before the emergence of gentamicin resistance harboured a 21 x 106-mol. wt penicillinase plasmid with the same restriction endonuclease profile as that from some MGRSA strains. Some MRSA strains carried other plasmids related to those found in MGRSA strains. %U https://www.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-20-2-157