Table 1.

Bacterial strains and plasmids used in this study

Designation Relevant markersaSource, derivation, and/or reference
Bacterial strains
E. coli K12
  ML4901F, galK2galT22 hsdR lacY1 metB1relA supE44 NA25 NA mutant from χ1037 (18)
  KU3999 ML4901 carrying pKU501, which produces TEM-1 and IMP-6 β-lactamases Conjugation from KU3838
  KU4866ML4901 carrying pKU502, which produces TEM-1 and IMP-6 β-lactamases Transferred pKU502 to ML4901
  KU4867ML4901 carrying pKU503, which produces IMP-6 β-lactamaseTransferred pKU503 to ML4901
  KU1917 ML4901 carrying pMS361, which produces IMP-1 β-lactamase Transferred pMS361 to ML4901 (16)
S. marcesens
  KU3838Clinical isolates carrying pKU501 This paper
Plasmids
 pKU501 Isolated from KU3838 This paper
 pKU502 1.5-kb fragment containing IMP-6 gene from pKU501 cloned into pBluescript This paper
 pKU503 1.5-kb fragment containing IMP-6 gene from pKU502 cloned into pHSG398 This paper
 pBluescript Cloning vector, TETr, AMPr 36
 pHSG398 Cloning vector, CHLr 37
 pMS361pHSG398 with insertion of 4.1-kb fragment of pMS354, a segregant plasmid derived from pMS35016
  • a Abbreviations: CHL, chloramphenicol; TET, tetracycline; AMP, ampicillin.