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Analysis of the resistance mediated by several R-factors to Tetracycline and Minocycline

Published online by Cambridge University Press:  14 April 2009

J. M. Robertson
Affiliation:
Institute of Animal Genetics, West Mains Mood, Edinburgh, EH9 3JN, Scotland
E. C. R. Reeve
Affiliation:
Institute of Animal Genetics, West Mains Mood, Edinburgh, EH9 3JN, Scotland
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The resistance levels conferred by the T-determinants in four R-factors to Tetracycline and Minocycline in cells of Escherichia coli K 12, before and after induction of maximum resistance by treatment with sub-inhibitory concentrations of the drugs, are measured by simple growth-and-challenge tests. The effect of a plasmid TK which confers tetracycline resistance on its host Klebsiella aerogenes is tested in the same way. The five T-determinants fall into a high-level and a low-level group for resistance, the former giving 3- to 4-fold higher resistance in both induced and uninduced cells than the latter. The T-determinants all confer much lower resistance to Minocycline (a tetracycline molecule modified at the C-6 and C-7 positions) than to Tetracycline. The main cause of this difference is that cells carrying a T-determinant exclude Minocycline much less efficiently than Tetracycline, but in addition Minocycline is less effective than Tetracycline in inducing increased resistance. These results are discussed in the light of a model put forward to explain the inducible nature of R-factor resistance to the tetracyclines.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1972

References

REFERENCES

Blackwood, R. K. & English, A. R. (1970). Structure – activity relationships in the tetra-cycline series. Advances in Applied Microbiology 13, 237266.CrossRefGoogle Scholar
Franklin, T. J. (1967). Resistance of Escherichia coli to tetracyclines. Changes in permeability to tetracyclines in Escherichia coli bearing transferable resistance factors. Biochemical Journal 105, 371378.CrossRefGoogle ScholarPubMed
Franklin, T. J. & Godfrey, A. (1965). Resistance of Eschericha coli to Tetracyclines. Biochemical Journal 94, 5460.CrossRefGoogle Scholar
Franklin, T. J. & Cook, J. M. (1971). R-factor with a mutation in the tetracycline resistance marker. Nature 229, 273274.CrossRefGoogle ScholarPubMed
Izaki, K. & Arima, K. (1963). Disappearance of Oxytetracycline accumulation in the cells of multiple drug-resistant Escherichia coli. Nature 200, 384385.CrossRefGoogle ScholarPubMed
Jarolmen, H., Hewel, D. & Kain, E. (1970). Activity of Minocycline against R-factor-carrying Enterobacteriaceae. Infection and Immunity 1, 321326.CrossRefGoogle ScholarPubMed
Redin, G. S. (1966). Antibacterial activity in mice of Minocycline, a new Tetracycline. Antimicrobial Agents and Chemotherapy – 1966 (ed. Hobby, G. L.), 371376. American Society of Microbiology.Google Scholar
Reeve, E. C. R. (1966). Characteristics of some single step mutants to chloramphenicol resistance in Escherichia coli K12 and their interactions with R-factor genes. Genetical Research 7, 281286.CrossRefGoogle ScholarPubMed
Reeve, E. C. R. (1968). Genetic analysis of some mutations causing resistance to tetracycline in Escherichia coli K12. Genetical Research 11, 303309.CrossRefGoogle ScholarPubMed
Reeve, E. C. R. (1970). Transfer characteristics of two resistance determinants in a wild strain of Klebsiella aerogenes (V9A). Genetical Research 16, 235240.CrossRefGoogle Scholar
Reeve, E. C. R. & Braithwaite, J. A. (1970). FK-lac, an episome with unusual properties found in a wild strain of a Klebsiella species. Nature 228, 162164.CrossRefGoogle Scholar
Sompolinsky, D., Krawitz, T., Zaidenzaig, Y. & Abramova, N. (1970 a). Indueible resistance to tetracycline in Staphylococcus aureus. Journal of General microbiology 62, 341349.CrossRefGoogle ScholarPubMed
Sompolinsky, D., Zaidenzaig, T., Ziegler-Schlomowitz, R. & Abramova, N. (1970 b). Mechanism of tetracycline resistance in Staphylococcus aureus. Journal of General Microbiology 62, 351362.CrossRefGoogle ScholarPubMed