Plasmid profiles and restriction enzyme fragmentation patterns of plasmids of methicillin-sensitive and methicillin-resistant isolates of Staphylococcus aureus from hospital and the community.
The number, frequency distribution and restriction enzyme fragmentation patterns of plasmids harboured by 163 methicillin-sensitive isolates of Staphylococcus aureus (MSSA) and 53 methicillin-resistant isolates (MRSA) were compared. Plasmids were demonstrated in less than half of the MSSA isolates; their frequency distribution did not differ from that predicted by a simple model of plasmid distributions. In contrast, all the MRSA isolates harboured plasmids, their distribution suggesting dissemination of a limited number of clones within the hospital. Among 72 MSSA isolates harbouring plasmids, 38 different restriction patterns were identified. There were fewer patterns among MRSA isolates; 11 were observed, and two predominant patterns accounted for 68% of those identified. These restriction patterns correlated with the presence or absence of aminoglycoside resistance. A multicopy plasmid of 2.6 kb was present in both MSSA and MRSA isolates that harboured more than one plasmid; it had the same restriction pattern irrespective of its source. The importance of these results in choosing a method of studying the spread of staphylococci is discussed.
CooksonB., TalsaniaH., NaidooJ., PhillipsI.1986; Strategies for typing and properties of epidemic methicillin-resistant Staphylococcus aureus. European Journal of Clinical Microbiology 5:702–709
DowdG., CafferkeyM., DouganG.1983; Gentamicin- and methicillin-resistant Staphylococcus aureus in Dublin hospitals; molecular studies. Journal of Medical Microbiology 16:129–138
GelmiM., ForestiI., RavizzolaG., BonfantiC., VerardiR., CarusoA., TuranoA.1987; Antibiotic resistances and plasmids in Staphylococcus aureus from Italian hospitals. Journal of Medical Microbiology 23:111–118
PlattD. J., SommervilleJ. S., KraftC. A., TimburyM. C.1984; Antimicrobial resistance and the ecology of Escherichia coli plasmids. Journal of Hygiene 93:181–188
PlattD. J., BrownD. J., MunroD. S.1986a; The distribution of plasmids among a representative collection of Scottish strains of salmonellae. Journal of Hygiene 97:199–204
PlattD. J.1987; A simple statistical approach that represents the frequency distribution of plasmids in clinical isolates of the enterobacteria. Journal of Medical Microbiology 23:255–260
PlikaytisB. D., CarloneG. M., EdmondsP., MayerL. W.1986; Robust estimation of standard curves for protein molecular weight and linear-duplex DNA base-pair number after gel electrophoresis. Analytical Biochemistry 152:346–364
TownsendD. E., AshdownN., MomohM., GrubbW. B.1985a; Distribution of plasmid-borne resistance to nucleic acid binding compounds in methicillin-resistant Staphylococcus aureus. Journal of Antimicrobial Chemotherapy 15:417–434
TownsendD. E., BoltonS., AshdownN., GrubbW. B.1985a; Transfer of plasmid-borne aminoglycoside resistance determinants in staphylococci. Journal of Medical Microbiology 20:169–185
Plasmid profiles and restriction enzyme fragmentation patterns of plasmids of methicillin-sensitive and methicillin-resistant isolates of Staphylococcus aureus from hospital and the community.