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In vitro evaluation of antibiotic synergy for NDM-1-producing Enterobacteriaceae

Béatrice Berçot1, Laurent Poirel, Laurent Dortet

  • 1Service de Bactériologie-Virologie, INSERM U914 'Emerging Resistance to Antibiotics', Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Faculté de Médecine et Université Paris-Sud, K.-Bicêtre, Paris, France. beatrice.bercot@lrb.aphp.fr

The Journal of Antimicrobial Chemotherapy
|August 3, 2011
PubMed
Abstract

Insights

Colistin, fosfomycin, and tigecycline showed limited in vitro synergy against New Delhi metallo-beta-lactamase 1 (NDM-1) producing enterobacteria. Most drug combinations demonstrated indifferent interactions, highlighting challenges in treating these resistant infections.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Antimicrobial Resistance

Background:

  • The rise of carbapenem-resistant Enterobacteriaceae (CRE) producing New Delhi metallo-beta-lactamase 1 (NDM-1) poses a significant global health threat.
  • Effective therapeutic options against NDM-1 producers are limited, necessitating the evaluation of existing antibiotics and combinations.

Purpose of the Study:

  • To evaluate the in vitro activity of colistin, fosfomycin, and tigecycline, individually and in combination, against NDM-1 producing enterobacteria.

Main Methods:

  • Minimum Inhibitory Concentrations (MICs) were determined for 28 NDM-1 producing enterobacterial isolates.
  • In vitro synergy testing using microdilution and chequerboard assays was performed on selected isolates.

Main Results:

  • One-third of NDM-1 producing isolates exhibited resistance or intermediate susceptibility to colistin, fosfomycin, or tigecycline.
  • Synergistic activity between colistin and fosfomycin, or colistin and tigecycline, was observed in rare instances.

Conclusions:

  • While some synergistic effects were noted, most drug interactions were indifferent, suggesting limited utility of these combinations.
  • Further research is needed to identify effective treatment strategies for NDM-1 producing enterobacterial infections.

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