Distribution and Genetic Location of Tn7 in Trimethoprim-Resistant Escherichia Coli
- 1 September 1986
- journal article
- research article
- Published by Microbiology Society in Journal of Medical Microbiology
- Vol. 22 (2) , 125-131
- https://doi.org/10.1099/00222615-22-2-125
Abstract
A series of 178 strains of Escherichia coli, highly resistant to trimethoprim, isolated from hospital patients and patients in the community between 1979 and 1983, was examined for the presence of Tn7 on a plasmid or on the chromosome only, by transposition to RP4 and restriction endonuclease digestion with Hind III. Of the isolates, 57% carried Tn7. Comparison of hospital isolates from 1979 to 1980 and 1982 showed that although the proportions that carried Tn7 were similar (63% and 57%) there had been a significant change in the genetic location of the transposon. The proportion of plasmid-mediated Tn7 had fallen from 62% to 30% with a corresponding rise in Tn7 located exclusively on the chromosome from 38% to 70%. This change may be the result of continuing transposition of Tn7 from plasmids to the bacterial chromosome followed by plasmid loss. The consequent reduction in the mobility of trimethoprim-resistance genes may in turn lead to changes in the incidence of resistance.This publication has 12 references indexed in Scilit:
- Distribution and transferability of plasmids in trimethoprim resistant urinary Escherichia coliJournal of Medical Microbiology, 1983
- Transferable Trimethoprim Resistance in Urinary Tract Pathogens Isolated in Finland and SwedenScandinavian Journal of Infectious Diseases, 1983
- Monitoring of plasmid-encoded, trimethoprim-resistant dihydrofolate reductase genes: detection of a new resistant enzymeAntimicrobial Agents and Chemotherapy, 1982
- Occurrence of transposable trimethoprim resistance in clinical isolates of Escherichia coli devoid of self-transmissible resistance plasmidsAntimicrobial Agents and Chemotherapy, 1982
- A simple method for the detection of resistance plasmids in Serratia species by transfer to members of the genus EnterobacterJournal of Antimicrobial Chemotherapy, 1981
- Specification of surface mating systems among conjugative drug resistance plasmids in Escherichia coli K-12Journal of Bacteriology, 1980
- Copy numbers of coexisting plasmids in Escherichia coli K-12Journal of Bacteriology, 1978
- Two Naturally Occurring Transposons Indistinguishable from Tn7Journal of General Microbiology, 1977
- Tn402: a new transposable element determining trimethoprim resistance that inserts in bacteriophage lambdaJournal of Bacteriology, 1977
- Transposition of a deoxyribonucleic acid sequence encoding trimethoprim and streptomycin resistances from R483 to other repliconsJournal of Bacteriology, 1976