Table 2.

Antimicrobial susceptibilities of representative isolates producing a single β-lactamase

StrainOrganismpI of enzymeMIC (μg/ml)a
AMPAMCSAMTICTIMPIPPTZCAZCTXATMIPMFOX
125 K. pneumoniae 5.6>1281632>128128>12816>1281640.12516
166 E. coli 5.6>1281616>12832322320.25160.12516
156 E. coli 6.1>1281632>128>128>1284>12832>1280.54
179 K. pneumoniae 6.1>1281616>128128>12841281320.1252
DH5α(pCLL2300) E. coli None44444210.25≤0.12≤0.120.254
DH5α(pCLL3416) E. coli 6.1>128168>12881280.5320.2540.58
  • a Abbreviations: AMP, ampicillin; AMC, amoxicillin plus clavulanic acid; SAM, ampicillin plus sulbactam, TIC, ticarcillin; TIM, ticarcillin plus clavulanic acid; PIP, piperacillin; PTZ, piperacillin plus tazobactam; CAZ, ceftazidime; CTX, cefotaxime; ATM, aztreonam; IPM, imipenem; FOX, cefoxitin.