Activity of NXL104 in combination with beta-lactams against genetically characterized Escherichia coli and Klebsiella pneumoniae isolates producing class A extended-spectrum beta-lactamases and class C beta-lactamases

Antimicrob Agents Chemother. 2011 May;55(5):2434-7. doi: 10.1128/AAC.01722-10. Epub 2011 Feb 28.


The novel non-β-lactam β-lactamase inhibitor NXL104, in combination with cefepime, ceftazidime, ceftriaxone, amdinocillin, and meropenem, was tested against 190 extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae isolates, 94 AmpC-hyperproducing E. coli isolates, and 8 AmpC/ESBL-coexpressing E. coli isolates. NXL104 restored 100% susceptibility to the partner cephalosporins for all isolates tested. Amdinocillin and meropenem MICs were modestly improved (2 to 32 times lower) by NXL104. These results suggest that NXL104 may be useful in combination with β-lactams for the treatment of infections caused by ESBL- and AmpC-producing Enterobacteriaceae.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Azabicyclo Compounds / pharmacology*
  • Escherichia coli / drug effects*
  • Escherichia coli / enzymology*
  • Escherichia coli / genetics
  • Klebsiella pneumoniae / drug effects*
  • Klebsiella pneumoniae / enzymology*
  • Klebsiella pneumoniae / genetics
  • beta-Lactamases / genetics
  • beta-Lactamases / metabolism*
  • beta-Lactams / pharmacology*


  • Azabicyclo Compounds
  • beta-Lactams
  • avibactam
  • beta-Lactamases