Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2009 Dec;47(12):4055-9.
doi: 10.1128/JCM.00959-09. Epub 2009 Oct 14.

Heteroresistance to meropenem in carbapenem-susceptible Acinetobacter baumannii

Alexandros Ikonomidis  1 , Evangelia Neou, Vassiliki Gogou, Georgia Vrioni, Athanassios Tsakris, Spyros Pournaras
Affiliations

Heteroresistance to meropenem in carbapenem-susceptible Acinetobacter baumannii

Alexandros Ikonomidis et al. J Clin Microbiol. 2009 Dec.

Abstract

The characteristics of carbapenem heteroresistance were studied in 14 apparently carbapenem-susceptible Acinetobacter baumannii isolates. The MICs for carbapenems were determined, and the isolates were genotyped by pulsed-field gel electrophoresis (PFGE) and sequence typing (ST). Population analysis, testing of the stability of the heteroresistant subpopulations, and time-killing assays were performed. The agar dilution MICs of both imipenem and meropenem for the native isolates ranged from 0.25 to 4 mg/liter. The isolates belonged to nine PFGE types and exhibited seven ST allelic profiles. Population analysis revealed subpopulations that grew in the presence of imipenem at concentrations of up to 8 mg/liter and meropenem at concentrations of up to 32 mg/liter. The meropenem-heteroresistant subpopulations of 11 isolates exhibited stable resistance with MICs that ranged from 16 to >32 mg/liter; their PFGE profiles were identical to those of the native isolates. Time-kill assays with meropenem revealed less pronounced killing for 10 isolates. These findings indicate that meropenem pressure can produce meropenem-heteroresistant subpopulations that might subsequently select for highly resistant strains.

PubMed Disclaimer

Figures

FIG. 1.
FIG. 1.
Time-killing assays for meropenem. The results for isolate AB13 are kept in each graph for comparison.
FIG. 2.
FIG. 2.
Population analysis assays for meropenem. The results for isolate AB13 are kept in each graph for comparison.
See this image and copyright information in PMC

Comment in

References

    1. Bergogne-Berezin, E., and K. J. Towner. 1996. Acinetobacter spp. as nosocomial pathogens: microbiological, clinical, and epidemiological features. Clin. Microbiol. Rev. 9:148-165. - PMC - PubMed
    1. Bogaerts, P., T. Naas, I. Wybo, et al. 2006. Outbreak of infection by carbapenem-resistant Acinetobacter baumannii producing the carbapenemase OXA-58 in Belgium. J. Clin. Microbiol. 44:4189-4192. - PMC - PubMed
    1. Castanheira, M., M. A. Toleman, R. N. Jones, F. J. Schmidt, and T. R. Walsh. 2004. Molecular characterization of a ß-lactamase gene, blaGIM-1, encoding a new subclass of metallo-ß-lactamase. Antimicrob. Agents Chemother. 48:4654-4661. - PMC - PubMed
    1. Clinical and Laboratory Standards Institute. 2006. Performance standards for antimicrobial susceptibility testing, 16th informational supplement. M100-S16. Clinical and Laboratory Standards Institute, Wayne, PA.
    1. Coelho, J. M., J. F. Turton, M. E. Kaufmann, J. Glover, N. Woodford, M. Warner, M. F. Palepou, R. Pike, T. L. Pitt, B. C. Patel, and D. M. Livermore. 2006. Occurrence of carbapenem-resistant Acinetobacter baumannii clones at multiple hospitals in London and Southeast England. J. Clin. Microbiol. 44:3623-3627. - PMC - PubMed

MeSH terms

LinkOut - more resources