Research Article

Dissemination of resistance plasmids among gentamicin-resistant enterobacteria from hospital patients.

Br Med J (Clin Res Ed) 1981; 283 doi: (Published 19 September 1981) Cite this as: Br Med J (Clin Res Ed) 1981;283:755
  1. S Knight,
  2. M Casewell


    Out of 184 patients who were infected or colonised with gentamicin-resistant enterobacteria, 17 (9%) harboured more than one strain. Single antibiotic-resistance plasmids were common to more than one of the different organisms isolated from nine patients, strongly suggestive of in-vivo conjugation. An "epidemic" plasmid with a molecular weight of approximately 110 megadaltons was found in 11 distinct strains isolated from four patients. Seven of the organisms harbouring this plasmid were Klebsiella aerogenes. Spread of multiple-resistance plasmids among endemic gentamicin-resistant enterobacteria is not uncommon, and these organisms provide a reservoir of plasmids that may ultimately spread to more pathogenic genera.