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Table 2 MIC data of selected β-lactams and characteristics of β-lactamases produced by clinical isolates of Enterobacteriaceae from Egypt

From: Characterization of CTX-M ESBLs in Enterobacter cloacae, Escherichia coli and Klebsiella pneumoniae clinical isolates from Cairo, Egypt

Clinical Isolate Enzyme characteristicsa Gene (s) detected by PCRb MIC (mg/L) of:
  pI CTX hydrolysis Inhibited by   CPD CPD/CLA FEP FEP/CLA FOX ATM IPM
    Clox CLA         
Kp4 5.4 No No Yes bla TEM >128 1 >128 0.06 8 128 0.12
Kp8 6.3 No No Yes -c >128 2 >128 0.06 8 128 0.12
Kp15 7.6 No No Yes bla SHV >128 2 >128 <0.03 8 128 0.12
  8.0 Yes No Yes bla CTX-M-14        
ENT 6.3 No No Yes -c >128 2 >128 <0.03 >16 32 0.25
  7.6 No No Yes -e        
  8.0 Yes No Yes bla CTX-M-14        
  8.9 No Yes No -d        
EC 5.4 No No Yes bla TEM >128 0.25 >128 <0.03 <4 16 0.12
  6.0 No No Yes -c        
  6.6 No No Yes -c        
  9.0 Yes No Yes bla CTX-M-15        
  1. CPD: cefpodoxime, CPD/CLA: cefpodoxime/clavulanic acid, FEP: cefepime, FEP/CLA: cefepime/clavulanic acid, FOX: cefoxitin, ATM: aztreonam, IPM: imipenem.
  2. aEnzyme Characteristics: pI: isoelectric point of crude β-lactamase extract preparations; CTX (0.75 mg/L) was used in the substrate-based IEF overlay technique, inhibitors used in the IEF overlay were clavulanic acid (1 mM) and cloxacillin (1 mM).
  3. b bla TEM, bla SHV and bla CTX-M genes were detected by PCR experiments using specific primers. Only the bla CTX-M genes were sequenced using primers that flanked the full-length genes (See Methods section).
  4. cPCR was not done to detect the gene that corresponds to the β-lactamase band on IEF gel.
  5. dβ-lactamase band focusing at pI value of 8.9, which is inhibited by cloxacillin, corresponds to the chromosomal ampC gene of E. cloacae (PCR data not shown).
  6. ePCR was negative