Methicillin-Resistant Staphylococci: Genetics of the Minority Population Free

Abstract

SUMMARY: A methicillin-resistant strain of (no. 5982) contained cocci with differing intrinsic resistances to methicillin. Most of the population was slightly more resistant than a typical methicillin-sensitive staphylococcal isolate, but a few were mutants with ability to grow at markedly increased concentrations of methicillin (500 μg./ml. or more). Penicillinase production was not essential for methicillin resistance since a penicillinase-negative variant of strain 5982 was able to produce penicillinase-negative strains with high degrees of methicillin resistance. Methicillin-sensitive strains also gave rise to mutants with increased intrinsic resistance to methicillin, but, in the mutants from methicillin-resistant strains, the increase in resistance was much greater. The mutants were characteristically slower growing than the wild type. Many were small colony variants which reverted to the parent type when passed in liquid media. With 5% NaCl-methicillin plates strain 5982 exhibited a phenotypic increase in resistance. On such plates a few L-type colonies were produced at high concentrations of methicillin.

Loading

Article metrics loading...

/content/journal/micro/10.1099/13500872-42-2-315
1966-02-01
2024-03-28
Loading full text...

Full text loading...

/deliver/fulltext/micro/42/2/mic-42-2-315.html?itemId=/content/journal/micro/10.1099/13500872-42-2-315&mimeType=html&fmt=ahah

References

  1. Ayliffe G. A. F., Barber M. 1963; Inactivation of benzylpenicillin and methicillin by hospital staphylococci. Br. med. J ii:202
    [Google Scholar]
  2. Baniö S. 1959; Transduction to penicillin and chloramphenicol resistance in Salmonella typhimurium. Genetics 44:449
    [Google Scholar]
  3. Barber M. 1964; Naturally occurring methicillin-resistant staphylococci. J. gen. Microbiol 35:183
    [Google Scholar]
  4. Demerec M. 1945; Production of staphylococcus strains resistant to various concentrations of penicillin. Proc. natn Acad. Sci., U.S.A 31:16
    [Google Scholar]
  5. Eriksen K. R., Erichsen I. 1963; Resistance to the newer penicillins. Br. med. J i:746
    [Google Scholar]
  6. Eriksen K. R., Erichsen I. 1964a; Resistance to methicillin, isoxazolyl penicillins and cephalothin in Staphylococcus aureus. Acta. path, microbiol. scand 62:255
    [Google Scholar]
  7. Eriksen K. R., Erichsen I. 1964b; Inactivation of methicillin, oxacillin, cloxacillin, and cephalothin by staphylococcal penicillinase. Acta path, microbiol. scand 62:399
    [Google Scholar]
  8. Gots J. S. 1945; The detection of penicillinase-producing properties of microorganisms. Science 102:309
    [Google Scholar]
  9. Gravenkemper C. F., Brodie J. L., Kirby W. M. M. 1965; Resistance of coagulase-positive staphylococci to methicillin and oxacillin. J. Bact 89:1005
    [Google Scholar]
  10. Hadley P., Delves E., Klimek J. 1931; The flltrable forms of bacteria. I. A filtrable stage in the life history of the Shiga dysentery bacillus. J. infect. Dis 48:1
    [Google Scholar]
  11. Hotchkiss R. D. 1951; Transfer of penicillin resistance in pneumococci by the desoxy-ribonucleate derived from resistant cultures. Cold Spr. Harb. Symp. quant. Biol 16:457
    [Google Scholar]
  12. Jevons M. P. 1961; ‘Celbenin’-resistant staphylococci. Br. med. J i:124
    [Google Scholar]
  13. Kagan B. M., Martin E. R., Stewart G. T. 1964; L-form induction of naturally occurring methicillin-resistant strains of Staphylococcus aureus. Nature, Lond 203:1031
    [Google Scholar]
  14. Knox R., Smith J. T. 1963; Stability of methicillin and cloxacillin to staphylococcal penicillinase. Br. med. J ii:205
    [Google Scholar]
  15. Novick R. P. 1962; Staphylococcal penicillinase and the new penicillins. Biochem. J 83:229
    [Google Scholar]
  16. Novick R. P. 1963; Analysis by transduction of mutations affecting penicillinase formation in Staphylococcus aureus. J. gen. Microbiol 33:121
    [Google Scholar]
  17. Novick R. P., Richmond M. H. 1965; Nature and interactions of the genetic elements governing penicillinase synthesis in Staphylococcus aureus. J. Bact 90:467
    [Google Scholar]
  18. Perrett C. J. 1954; Iodometric assay of penicillinase. Nature, Lond 174:1012
    [Google Scholar]
  19. Richmond M. H. 1963; Purification and properties of the exopenicillinase from Staphylococcus aureus. Biochem. J 88:452
    [Google Scholar]
  20. Roantree R. J., Steward J. P. 1965; Mutations to penicillin resistance in the Enterobacteriaceae that affect sensitivity to serum and virulence for the mouse. J. Bact 89:630
    [Google Scholar]
  21. Seligman S. J. 1966; Penicillinase-negative varients of methicillin-resistant Staphyloccus aureus. Nature, Lond in press
    [Google Scholar]
  22. Seligman S. J., Hewitt W. L. 1965; Mutation of Escherichia coli to increased resistance to ampicillin. Antimicrobiol. Agents and Chemotherapy–1964344
    [Google Scholar]
  23. Stewart G. T., Holt R. J. 1963; Evolution of natural resistance to the newer penicillins. Br. med. J i:308
    [Google Scholar]
  24. Sutherland R., Rolinson G. N. 1964; Characteristics of methicillin-resistant staphylococci. J. Bact 87:887
    [Google Scholar]
  25. Youmans G. P., Wiixiston E. H., Simon M. 1945; Production of small colony variants by the action of penicillin. Proc. Soc. exp. Biol. Med 58:56
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/micro/10.1099/13500872-42-2-315
Loading
/content/journal/micro/10.1099/13500872-42-2-315
Loading

Data & Media loading...

Most cited Most Cited RSS feed