Journal Article

Outbreak of multi-resistant <i>Klebsiella oxytoca</i> involving strains with extended-spectrum β-lactamases and strains with extended-spectrum activity of the chromosomal β-lactamase

Dominique Decré, Béatrice Burghoffer, Valérie Gautier, Jean-Claude Petit and Guillaume Arlet

in Journal of Antimicrobial Chemotherapy

Published on behalf of British Society for Antimicrobial Chemotherapy

Volume 54, issue 5, pages 881-888
Published in print November 2004 | ISSN: 0305-7453
Published online November 2004 | e-ISSN: 1460-2091 | DOI:
Outbreak of multi-resistant Klebsiella oxytoca involving strains with extended-spectrum β-lactamases and strains with extended-spectrum activity of the chromosomal β-lactamase

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Objectives: This study was conducted to analyse broad-spectrum cephalosporin-resistant Klebsiella oxytoca strains.

Methods: The 57 isolates studied were recovered from clinical specimens (n=23) or from rectal swabs (n=34) during a 26-month period. Antibiotic susceptibility patterns were determined using standard agar diffusion and dilution methods including the synergy test between extended-spectrum cephalosporins and clavulanic acid. ERIC-2 PCR and pulsed-field gel electrophoresis (PFGE) methods were used to study the clonal relatedness of the strains. Plasmid-mediated and chromosomal β-lactamases were characterized by mating and specific bla gene amplification and sequencing.

Results: Four different antibiotic resistance patterns were identified whereas ERIC-2 PCR and PFGE revealed six main profiles. Extended-spectrum β-lactamases (ESBLs) were found in 32 strains: TEM-7 (n=26), TEM-129 (n=1), TEM-3 (n=4), SHV-2 (n=1). The new TEM-type β-lactamase, TEM-129, differed from TEM-7 by one mutation (Glu-104→Lys). All TEM-7 or TEM-129 producers were genetically related. Twenty-five other strains with identical ERIC-2 PCR and PFGE profiles harboured a blaOXY-2 gene different from the reference gene: 24 strains displayed one substitution (Ala-237→Ser) in the KTG motif and one strain, highly resistant to ceftazidime, showed an additional substitution (Pro-167→Ser).

Conclusions: The study demonstrated that the majority of strains (n=52) harbouring the OXY-2-type β-lactamase corresponded to two clones. The first clone (n=27) corresponded to ESBL-producing strains. The second clone (n=25) displayed extended-spectrum activity of the chromosomal β-lactamase.

Keywords: OXY-2 β-lactamase; TEM-7; TEM-129

Journal Article.  4850 words.  Illustrated.

Subjects: Medical Oncology ; Critical Care

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