Table 1.

Plasmids used in the study

PlasmidEnzymeOriginReference
pMG226TEM-6Munich, Germany 2, 11
pMG223TEM-10Boston, Mass. 11, 31
pMG224TEM-12Cambridge, Mass. 30, 31
pMG225TEM-26Cambridge, Mass. 30, 31
pMG229SHV-2Paris, France 11, 13
pMG258SHV-2a Boston, Mass.This paper
pDU18SHV-3Paris, France 24
pMG257SHV-5a Boston, Mass.This paper
pMG233AmpCb Providence, R.I. 26
pMG245AmpCb Boston, Mass. 12
pMG248AmpCc Durham, N.C. 12
pMG250AmpCd Ann Arbor, Mich. 12
pMG252AmpCe Birmingham, Ala. 21
  • a Presumptive identification based on pI determination.

  • b Enterobacter cloacae type.

  • c Sequence not yet analyzed.

  • d C. freundii type.

  • e Related to the group of AmpC-type β-lactamases distantly related to the chromosomal enzyme of P. aeruginosa.