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Published on: September 9, 2015

In vitro activity of doripenem against Acinetobacter baumannii clinical isolates

Sara Marti1, Javier Sánchez-Céspedes, Verónica Alba

  • 1Servei de Microbiologia, Centre de Diagnòstic Biomèdic, Hospital Clínic, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.

International Journal of Antimicrobial Agents
|November 4, 2008
PubMed

Insights

Doripenem shows superior in vitro activity against Acinetobacter baumannii strains with the bla(OXA-58) gene compared to imipenem and meropenem. Isolates with the bla(OXA-24) gene were resistant to all tested carbapenems.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pharmacology

Background:

  • Acinetobacter baumannii is a significant cause of hospital-acquired infections.
  • Carbapenem resistance in A. baumannii is a growing global health concern.
  • Carbapenemases, such as OXA-type enzymes, are key mechanisms of resistance.

Purpose of the Study:

  • To evaluate the in vitro activity of doripenem against clinical isolates of Acinetobacter baumannii.
  • To compare doripenem's efficacy with imipenem and meropenem, particularly in relation to specific carbapenemase genes.
  • To assess the impact of bla(OXA-58) and bla(OXA-24) genes on doripenem susceptibility.

Main Methods:

  • In vitro susceptibility testing of doripenem, imipenem, and meropenem against 87 Acinetobacter baumannii clinical isolates.
  • Detection and characterization of carbapenemase genes, including bla(OXA-58) and bla(OXA-24).
  • Determination of minimum inhibitory concentrations (MICs) for each antibiotic against the isolates.

Main Results:

  • Doripenem demonstrated superior in vitro activity against A. baumannii isolates harboring the bla(OXA-58) gene compared to imipenem and meropenem.
  • Isolates expressing the bla(OXA-24) gene were resistant to doripenem, imipenem, and meropenem.
  • A lower percentage of bla(OXA-58) positive isolates exhibited high-level doripenem resistance (MIC >8 µg/mL) than with imipenem or meropenem.

Conclusions:

  • Doripenem offers a potential therapeutic advantage over imipenem and meropenem for treating A. baumannii infections mediated by the bla(OXA-58) carbapenemase.
  • The presence of bla(OXA-24) confers resistance to doripenem, imipenem, and meropenem, highlighting the importance of genotypic resistance detection.
  • These findings underscore the need for susceptibility testing to guide antibiotic selection for A. baumannii infections.

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