TABLE 1.

In vitro activity of several antimicrobial agents against ESBL-producing E. coli and K. pneumoniae isolates

AgentE. coliK. pneumoniae
MIC range (μg/ml)MIC50 (μg/ml)MIC90 (μg/ml)%SaMIC range (μg/ml)MIC50 (μg/ml)MIC90 (μg/ml)%S
Cefotaxime0.06->64>64>640≤0.03->6432>640
Ceftazidime0.5->6416>6402->6432>640
Cefepime≤0.03->648>640≤0.03->642>640
Aztreonam0.125->648>6400.125->648>640
Cefpodoxime0.5-5121282560≤0.25-512642560
Cefoxitin1-25641676.51-2564894
Cefotetan≤0.25-321298≤0.25-32≤0.250.598.5
Amoxicillin-clavulanate (2:1)2/1-128/648/432/16694/2-128/6416/832/1640
Ticarcillin-clavulanate (2 μg/ml)≤0.5->1,024128>1,02413≤0.5->1,024256>1,0247
Piperacillin-tazobactam (4 μg/ml)≤0.5->1,024212885≤0.5->1,0244>1,02474
Imipenem≤0.06-10.1250.25100≤0.06-0.50.1250.25100
Meropenem≤0.06-0.25≤0.06≤0.06100≤0.06-0.125≤0.06≤0.06100
Amikacin0.5-12821693.50.5-6411691
Gentamicin0.125->1281128660.5->12832>12833
Tobramycin0.25->128164650.25-12883238.5
Ciprofloxacin≤0.06->128412837.5≤0.06-640.125288.5
Co-trimoxazole≤4.75/0.25->608/32304/16>608/3225≥4.75/0.25->608/3219/1608/3240
  • a %S, percent susceptibility.