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Published on: February 1, 2018
First detection of plasmid-encoded blaOXY beta-lactamase
J J González-López1, A Coelho, M N Larrosa
1Department of Microbiology, Hospital Vall d'Hebron, Passeig Vall d'Hebron 119-129, Barcelona, Spain. jjgonzalez@ir.vhebron.net
Insights
This study identifies a novel plasmid-borne OXY beta-lactamase (bla(OXY-1)) in Klebsiella species from pediatric patients. This finding is crucial for understanding antimicrobial resistance in hospital settings.
Area of Science:
- Microbiology
- Infectious Diseases
- Molecular Biology
Background:
- Klebsiella species are significant nosocomial pathogens.
- Beta-lactamase enzymes contribute to antimicrobial resistance.
- OXY beta-lactamases are increasingly recognized in Gram-negative bacteria.
Purpose of the Study:
- To characterize the genetic basis of OXY beta-lactamase hyperproduction in clinical Klebsiella isolates.
- To investigate the role of plasmids in the dissemination of bla(OXY-1).
Main Methods:
- Phenotypic susceptibility testing of Klebsiella isolates.
- Plasmid analysis including size determination and transfer experiments (electrotransformation and conjugation).
- Identification and sequencing of beta-lactamase and quinolone resistance genes.
Main Results:
- Three Klebsiella oxytoca and one Klebsiella pneumoniae isolate showed resistance patterns indicative of OXY beta-lactamase hyperproduction.
- A 95-kb plasmid carrying the bla(OXY-1) gene was identified in all isolates.
- The bla(OXY-1) gene was transferable via electrotransformation but not conjugation.
- The plasmid also harbored the qnrS1 gene, conferring quinolone resistance.
Conclusions:
- This is the first report of a plasmid-encoded OXY beta-lactamase (bla(OXY-1)).
- Plasmid-mediated OXY beta-lactamase production can contribute to antimicrobial resistance in Klebsiella.
- The co-harboring of bla(OXY-1) and qnrS1 on the same plasmid highlights the potential for co-selection of resistance.
Abstract:
Three Klebsiella oxytoca isolates and one Klebsiella pneumoniae isolate from three children admitted to the Hematology Unit of Hospital Vall d'Hebron (Barcelona, Spain) exhibited a susceptibility pattern suggesting OXY beta-lactamase hyperproduction. All the isolates contained a 95-kb plasmid that harbored bla(OXY-1), which was transferred by electrotransformation but could not be self-transferred by conjugation. A qnrS1 gene was also harbored in the bla(OXY-1)-carrying plasmid. This is the first report of a plasmid-encoded OXY beta-lactamase.
