Characterisation of trimethoprim resistance transposons and their gene products

A faecal enterobacterial strain, P-20, isolated from pigs, was shown to owe its trimethoprim resistance to two different plasmid/transposon mediated resistance genes. One gene, mobilised by RP4, was located on a 4 - 6 kb transposon designated Tn4135, and resulted in the mediation of transferable high level trimethoprim resistance of greater than 1000 ug/ml. Biochemical investigation of the transposon gene product revealed a close resemblence between the trimethoprim resistant dihydrofolate reductase (DHFR) of Escherichia coli J62(RP4::Tn4135) and that of the type I plasmid enzyme, encoded by RP4::Tn7_. Despite the differences in transposon size, this marked similarity between the two DHFRs suggests a similar evolutionary origin for the two transposons and reiterates the potential of trimethoprim resistance transfer between animal and human resevoirs

Grantor dc:publisher

The University of Edinburgh

Year dc:date.issued

1988

Author dc:creator

• McKay Thomson, Stephanie

Handle dc:identifier.uri

http://hdl.handle.net/1842/29264

OAI identifier oai:identifier

oai:era.ed.ac.uk:1842/29264