Journal Article

Characterization of a new integron containing <i>bla</i><sub>VIM-1</sub> and <i>aac(6′)</i>-<i>IIc</i> in an <i>Enterobacter cloacae</i> clinical isolate from Greece

Irene Galani, Maria Souli, Zoi Chryssouli, Konstantina Orlandou and Helen Giamarellou

in Journal of Antimicrobial Chemotherapy

Volume 55, issue 5, pages 634-638
Published in print May 2005 | ISSN: 0305-7453
Published online May 2005 | e-ISSN: 1460-2091 | DOI:
Characterization of a new integron containing blaVIM-1 and aac(6′)-IIc in an Enterobacter cloacae clinical isolate from Greece

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  • Medical Oncology
  • Critical Care


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Objectives: A clinical isolate of Enterobacter cloacae exhibiting reduced susceptibility to imipenem and a positive EDTA-disc synergy test was studied for carbapenemase production.

Materials and methods: MICs were determined with standard procedures as well as using a higher inoculum. Isoelectric focusing of cell extracts was used for detection of β-lactamases. PCR assays with primers specific for the blaVIM gene and the conserved segments of class 1 integrons and sequence analyses were carried out to identify the gene and to map the metallo-β-lactamase encoding integron. Transferability of the gene was assessed with conjugation experiments using the filter mating technique. To identify the location of the blaVIM-1 gene, Southern hybridization was carried out in genomic DNA using an internal fragment of the blaVIM-1 gene as a probe, amplified by PCR.

Results: The isolate was resistant to extended-spectrum β-lactams. The MICs of carbapenems were below the resistance breakpoints but rose above resistance breakpoints when an inoculum of 108 cfu/mL was used. Isoelectric focusing detected a β-lactamase with a pI of 6.1, which exhibited imipenem-hydrolysing activity in a microbiological assay. Ceftazidime and imipenem resistance were not transferable by conjugation. PCR assays identified the blaVIM-1 gene in the variable region of a class 1 integron which also carried the aac(6′)-IIc gene. The blaVIM-1 probe hybridized with an approximately 130 kb fragment of genomic DNA, suggesting a chromosomal location of the gene.

Conclusion: We describe a novel class 1 integron containing blaVIM-1 and aac(6′)-IIc genes in an E. cloacae clinical isolate.

Keywords: metallo-β-lactamases; carbapenemases; E. cloacae

Journal Article.  2523 words.  Illustrated.

Subjects: Medical Oncology ; Critical Care

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