Table 2.

Antimicrobial susceptibility profiles of E. coli strains used in conjugation and expression experimentsa

StrainDesignationMIC (μg/ml)
Amo Amp Cef Cet Cep Fox CmlKanNalStrSulTet
CVM1320Donor>32 >32 8 16>32 >32 ≤4≤16≤4 128 ≤128>32
CVM990Recipient44≤0.5≤0.258≤4≤4>64 ≤4>256 >512 >32
1320/990Transconjugant>32 >32 >16 64 >32 >32 8>64 ≤4>256 >512 >32
JM263Recipient881≤0.25 32 32 32 ≤16>256 ≤32≤1288
1320/263Transconjugant>32 >32 >16 64 >32 32 ≤16>256 ≤32≤1288
BL21(DE3)pLysSHost cell2≤2≤0.5≤0.252≤4>32 ≤16≤4≤32≤128≤4
BL21(DE3)pLysS + pET34bHost cell + vector2≤2≤0.5≤0.252≤4>32 >64 ≤4≤32≤128≤4
BL21 (DE3)pLysS + pET34b-cmyTransformant>32 >32 8 4>32 16>32 >64 ≤4≤32≤128≤4
  • a Amo, amoxicillin-clavulanic acid; Amp, ampicillin; Cef, ceftiofur; Cet, ceftriaxone; Cep, cephalothin; Fox, cefoxitin; Cml, chloramphenicol; Kan, kanamycin; Nal, nalidixic acid; Str, streptomycin; Sul, sulfamethoxazole; Tet, tetracycline. All isolates were susceptible to amikacin, apramycin, ciprofloxacin, gentamicin, and trimethoprim-sulfamethoxazole. β-Lactam antimicrobials are bolded and italicized. MICs were determined via broth microdilution methods in accordance with NCCLS guidelines (12, 13). Resistance is indicated by boldface values.