1887

Abstract

Growth of two independently isolated strains of methicillin-resistant (MRSA) in increasing concentrations of methicillin (step-selection) resulted in increased resistance in these strains. When chromosomal DNA from the step-selected variants was probed using DNA sequences previously demonstrated to be associated with methicillin resistance in MRSA strains, amplification of the homologous chromosomal sequence was identified. Growth of these step-selected strains in the absence of methicillin resulted in loss of the amplified sequence, while the original sequence remained. There are differences between the two strains in the stability of maintenance of amplified sections. Prolonged storage of the variants on a high concentration of methicillin resulted in loss of amplified sections without concomitant loss of methicillin resistance. Thus amplification may be only one of at least two molecular mechanisms available to to increase methicillin resistance in response to step-selection. Probing of cells of the highly resistant sub-population of a heterogeneously resistant MRSA strain showed that duplication of this -associated DNA is not involved in the mechanism of heteroresistance.

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1988-06-01
2024-04-19
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References

  1. Beck W. D., Berger-Bachi B., Kayser F. H. 1986; Additional DNA in methicillin-resistant Staphylococcus aureus and molecular cloning of mec- specific DNA. Journal of Bacteriology 165:373–378
    [Google Scholar]
  2. Cohen S., Sweeney H. M. 1970; Transduction of methicillin resistance in Staphylococcus aureus dependent on an unusual specificity of the recipient strain. Journal of Bacteriology 104:1158–1167
    [Google Scholar]
  3. Dyke K. G. H. 1969; Penicillinase production and intrinsic resistance to penicillins in methicillin- resistant cultures of Staphylococcus aureus. Journal of Medical Microbiology 2:261–278
    [Google Scholar]
  4. Fontana R. 1985; Penicillin-binding proteins and the intrinsic resistance to β-lactams in Grampositive cocci. Journal of Antimicrobial Chemotherapy 16:412–416
    [Google Scholar]
  5. Gillespie M. T., Lyon B. R., Loo L. S. L., Matthews P. R., Stewart P. R., Skurray R. A. 1987; Homologous direct repeat sequences associated with mercury, methicillin, tetracycline and trimethoprim resistance determinants in Staphylococcus aureus. FEMS Microbiology Letters 43:165–171
    [Google Scholar]
  6. Hartman B. J., Tomasz A. 1986; Expression of methicillin resistance in heterogeneous strains of Staphylococcus aureus. Antimicrobial Agents and Chemotherapy 29:85–92
    [Google Scholar]
  7. Heneine N., Stewart P. R. 1986; Physiological determination of methicillin resistance in Staphylococcus aureus: comparison of clinical and genetically derived isolates. Journal of Antimicrobial Chemotherapy 17:705–715
    [Google Scholar]
  8. Inglis B., Matthews P. R., Stewart P. R. 1988; The expression in Staphylococcus aureus of cloned DNA encoding methicillin resistance. Journal of General Microbiology 134:1465–1469
    [Google Scholar]
  9. Johnson D. A., Gautsch J. W., Sportsman J. R., Elder J. H. 1984; Improved technique involving nonfat dry milk for analysis of proteins and nucleic acids transferred to nitrocellulose. Gene Analytical Techniques 1:3–8
    [Google Scholar]
  10. Lyon B. R., Skurray R. A. 1987; Antimicrobial resistance of Staphylococcus aureus: genetic basis. Microbiological Reviews 51:88–134
    [Google Scholar]
  11. Maniatis T., Fritsch E. F., Sambrook J. 1982 Molecular Cloning: a laboratory Manual Cold Spring Harbor, New York: Cold Spring Harbor Laboratory;
    [Google Scholar]
  12. Matsuhashi M., Dong Song M., Ishino F., Wachi M., Doi M., Inoue M., Ubukata K., Yamashita N., Konno M. 1986; Molecular cloning of the gene of a penicillin-binding protein supposed to cause high resistance to β-lactam antibiotics in Staphylococcus aureus. Journal of Bacteriology 167:975–980
    [Google Scholar]
  13. Matthews P. R., Stewart P. R. 1984; Resistance heterogeneity in methicillin resistant Staphylococcus aureus. FEMS Microbiology Letters 22:161–166
    [Google Scholar]
  14. Matthews P. R., Reed K. C., Stewart P. R. 1987; The cloning of chromosomal DNA associated with methicillin and other resistances in Staphylococcus aureus. Journal of General Microbiology 133:1919–1929
    [Google Scholar]
  15. Reynolds P. E., Fuller C. 1986; Methicillin- resistant strains of Staphylococcus aureus : presence of identical additional penicillin-binding protein in all strains examined. FEMS Microbiology Letters 33:251–254
    [Google Scholar]
  16. Sabath L. D., Wallace S. J., Gerstein D. A. 1972; Suppression of intrinsic resistance to methicillin and other penicillins in Staphylococcus aureus. Antimicrobial Agents and Chemotherapy 2:350–355
    [Google Scholar]
  17. Southern E. M. 1975; Detection of specific sequences among DNA fragments separated by gel electrophoresis. Journal of Molecular Biology 98:503–517
    [Google Scholar]
  18. Stark G. R., Wahl G. M. 1984; Gene amplification. Annual Review of Biochemistry 53:447–491
    [Google Scholar]
  19. Stewart P. R., Waldron H. G., Lee J. S., Matthews P. R. 1985; Molecular relationships among serogroup B bacteriophages of Staphylococcus aureus. Journal of Virology 55:111–116
    [Google Scholar]
  20. Wahl G. M., Stern M., Stark G. R. 1979; Efficient transfer of large DNA fragments from agarose gels to diazobenzyloxymethyl-paper and rapid hybridization by using dextran sulphate. Proceedings of the National Academy of Sciences of the United States of America 76:3683–3687
    [Google Scholar]
  21. Wilson C. R., Morgan A. E. 1985; Chromosomal DNA amplification in Bacillus subtilis. Journal of Bacteriology 163:445–453
    [Google Scholar]
  22. Young M. 1984; Gene amplification in Bacillus subtilis. Journal of General Microbiology 130:1613–1621
    [Google Scholar]
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