Susceptibility to Antimicrobial Agents and Analysis of Plasmids in Gentamicin- and Methicillin-Resistant Staphylococcus Aureus From Dublin Hospitals Coleman, D. C. and Pomeroy, H. and Estridge, J. K. and Keane, C. T. and Cafferkey, M. T. and Hone, R. and Foster, T. J.,, 20, 157-167 (1985), doi = https://doi.org/10.1099/00222615-20-2-157, publicationName = Microbiology Society, issn = 0022-2615, abstract= 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., language=, type=