Journal article

CTX-M-33 Is a CTX-M-15 derivative conferring reduced susceptibility to carbapenems

  • Poirel, Laurent Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland - INSERM European Unit, IAME, Paris, France
  • Ortiz de la Rosa, José Manuel Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland
  • Richard, Anaïs Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland
  • Aires-de-Sousa, Marta Escola Superior de Saúde da Cruz Vermelha Portuguesa, Lisbon, Portugal
  • Nordmann, Patrice Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland - INSERM European Unit, IAME, Paris, France - Swiss National Reference Center for Emerging Antibiotic Resistance, Fribourg, Switzerland
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    01.12.2019
Published in:
  • Antimicrobial Agents and Chemotherapy. - 2019, vol. 63, no. 12
English CTX-M-type extended-spectrum β-lactamases (ESBLs) are widespread among Enterobacterales strains worldwide. The most common variant is CTX-M-15, which hydrolyzes ceftazidime at a high rate but spares carbapenems. Here, we identified CTX-M-33, a point mutation derivative of CTX-M-15 (Asp to Ser substitution at Ambler position 109) that exhibited low carbapenemase activity. β-Lactamase CTX-M-33 was identified in a Klebsiella pneumoniae isolate, belonging to sequence type 405 and lacking the outer membrane protein OmpK36, that was resistant to broad-spectrum cephalosporins and β-lactam/β-lactamase inhibitor combinations and displayed decreased susceptibility to carbapenems. Comparative hydrolytic activity assays showed that CTX-M-33 hydrolyzed ceftazidime at a lower level than CTX-M-15 but significantly hydrolyzed meropenem. In addition, CTX-M-33 showed higher mutant prevention concentration values and a wider mutant selection window in the presence of meropenem, in accordance with its observed hydrolytic properties. Here, we identified the very first CTX-M enzyme possessing weak carbapenemase activity, which may correspond to an emerging phenomenon, considering its possible evolution from the widespread ESBL CTX-M-15.
Faculty
Faculté des sciences et de médecine
Department
Médecine 3ème année
Language
  • English
Classification
Biology
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/308393
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