1887

Abstract

SUMMARY: Small amounts of proflavine were added at intervals of 30 min. to growing cultures of . Additions during the logarithmic phase gave an increase of resistance of two- or threefold in a high proportion of organisms. Additions in the lag or late logarithmic phase gave no such increase, although the resistance of the organisms themselves was higher in these phases. Whether organisms were able to grow in the presence of proflavine, therefore, depended not only on their resistance but on the conditions in the culture medium. The increase in proflavine resistance, which occurred when drug was added to growing cultures, was not accompanied by increase of cross-resistance to other drugs. The resistance was lost on growth in the absence of drug. For these reasons, the increase is held to be a phenotypic adaptation. There was also an increase in the number of organisms with a high resistance, of the order of that of mutants. These organisms showed cross resistance with other drugs.

Partial synchronization of division was achieved by the temporary cooling of cultures. These synchronized cultures showed cycles of division of about 30 min. They also showed cycles of resistance of . 20 min. Evidence is presented for the view that the organisms undergo cycles of varying adaptability to proflavine resistance. It is suggested that this variation in adaptability can explain the range of resistance found in an ordinary sensitive culture. It can also explain the effect of proflavine additions in raising the resistance of a high proportion of organisms in a growing culture.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-20-2-384
1959-04-01
2024-12-05
Loading full text...

Full text loading...

/deliver/fulltext/micro/20/2/mic-20-2-384.html?itemId=/content/journal/micro/10.1099/00221287-20-2-384&mimeType=html&fmt=ahah

References

  1. Cavalli L. L. 1952; Genetic analysis of drug-resistance. Bull. Wld Hlth Org 6:185
    [Google Scholar]
  2. Hotchkiss R. D. 1954; Cyclical behaviour in pneumococcal growth and transformability occasioned by environmental changes. Proc. nat. Acad. Sci., Wash 40:49
    [Google Scholar]
  3. Hughes W. H. 1952; Variation in penicillin resistance in single-cell cultures of Staphylococcus aureus . J. gen. Microbiol 6:175
    [Google Scholar]
  4. Hughes W. H. 1955; The differences in antibiotic sensitivity of closely related single cells of Proteus vulgaris . J. gen. Microbiol 12:269
    [Google Scholar]
  5. Maruyama Y., Yanagita T. 1956; Physical methods for obtaining synchronous culture of Escherichia coli . J. Bact 71:542
    [Google Scholar]
  6. Sinai J., Yudkin J. 1959; The origin of bacterial resistance to proflavine. 3. The alleged rapid adaptation to proflavine resistance in Bacterium lactis aerogenes (syn Aerobader aerogenes, Klebsiella pneumoniae). J. gen. Microbiol 20:373
    [Google Scholar]
  7. Szybalski W. 1952; Gradient plate technique for study of bacterial resistance. Science 116:46
    [Google Scholar]
  8. Thornley M. J., Yudkin J. 1959; The origin of bacterial resistance to proflavine. 2. Spontaneous mutation to proflavine resistance in Escherichia coli . J. gen. Microbiol 20:365
    [Google Scholar]
  9. Yudkin J. 1953; Origin of acquired drug resistance in bacteria. Nature; Land: 171541
    [Google Scholar]
/content/journal/micro/10.1099/00221287-20-2-384
Loading
/content/journal/micro/10.1099/00221287-20-2-384
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error