Table 1

Resistance phenotype, genotype, and genetic elements of E. coli strain W635, transconjugants (TC), and recipient straina

StrainMIC (μg/ml) ofb:Resistance gene(s)Amino acid change(s) detectedClass 1 integronIncompatibility group detected (size of plasmid)
AMPATMIPMMEMSTRTMPGyrAParC
W635 donor>128812832128>128blaTEM-1bblaIMI-2strA-strBcsul1 sul2S83L, D87NS80IdfrA1 aadA1IncI1 (97 kb), IncF (48.5 kb), ColETP (<10 kb)
TC1>128812816>128>128blaTEM-1bblaIMI-2strA-strBsul1 sul2NDNDdfrA1 aadA1IncI1/IncF (160 kb),d ColETP (<10 kb)
TC15>1280.1250.250.032>128>128blaTEM-1bstrA-strBsul1 sul2NDNDdfrA1 aadA1IncI1 (97 kb)
CSH26 recipient160.1250.250.0324<0.125NDNDNDND
  • a ND, not determined; –, not detected.

  • b AMP, ampicillin; ATM, aztreonam; IPM, imipenem; MEM, meropenem; STR, streptomycin; TMP, trimethoprim.

  • c strA-strB genes were linked to the sul2 gene (repC-sul2-strA-strB-ISCR2).

  • d IncI1 and IncF were detected by hybridization in a plasmid of approximately 160 kb in the blaIMI-2-positive TC1 transconjugant.