Table 1.

Bacterial strains and plasmids used in this study

Strain or plasmidRelevant genotype or phenotypeSource or reference
E. coli DH10BF′mcrA Δ (mrr hsdRMS mrcBC)F80dlacZDM15 Δ lacX74 deoR recA1 endA1 ara Δ 139 Δ (ara leu)7697 galU galK1 rpsL nupG Gibco BRL-Life Technologies
 In vitro-obtained rifampin-resistant E. coli DH10BRifampin resistantThis study
E. coli NCTC 50192154-, 66-, 48-, and 7-kb reference plasmids 14
K. pneumoniae ORI-1Extended spectrum cephalosporin resistantThis study
 pBK-CMV phagemidNeor Kanr Stratagene
 pTK1Natural plasmid from K. pneumoniae ORI-1 containing bla GES-1 conferring the studied expanded-resistance phenotypeThis study
 pC1Recombinant plasmid with a 4.5-kb HindIII insert from pTK1 containing bla GES-1 into pBK-CMVThis study