GES-66, Characterization of a new β-lactamase Gene Variant Detected in Klebsiella pneumoniae

Florencia Martino^{1

2}, Denise De Belder³, Melina Rapoport², Renata Monge⁴, Agustina Forastiero⁴, Kara A Moser⁵, Valeria Fabre¹, Alejandra Corso², Fernando Pasteran²

Affiliations

¹ Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
² Servicio Antimicrobianos, National Reference Laboratory in Antimicrobial Resistance (NRLAR), National Institute of Infectious Diseases (INEI), ANLIS "Dr. Carlos G. Malbrán", Buenos Aires, Argentina.
³ UO Centro Nacional de Genómica y Bioinformática, National Center of Genomics and Bioinformatics, ANLIS "Dr. Carlos G. Malbrán", Buenos Aires, Argentina.
⁴ Laboratorio del Hospital Británico de Buenos Aires, Buenos Aires, Argentina.
⁵ Clinical and Environmental Microbiology Branch, Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.

PMID: 40465844
DOI: 10.1093/infdis/jiaf302

GES-66, Characterization of a new β-lactamase Gene Variant Detected in Klebsiella pneumoniae

Florencia Martino et al. J Infect Dis. 2025.

. 2025 Jun 4:jiaf302.

doi: 10.1093/infdis/jiaf302. Online ahead of print.

Authors

Florencia Martino^{1

2}, Denise De Belder³, Melina Rapoport², Renata Monge⁴, Agustina Forastiero⁴, Kara A Moser⁵, Valeria Fabre¹, Alejandra Corso², Fernando Pasteran²

Affiliations

¹ Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
² Servicio Antimicrobianos, National Reference Laboratory in Antimicrobial Resistance (NRLAR), National Institute of Infectious Diseases (INEI), ANLIS "Dr. Carlos G. Malbrán", Buenos Aires, Argentina.
³ UO Centro Nacional de Genómica y Bioinformática, National Center of Genomics and Bioinformatics, ANLIS "Dr. Carlos G. Malbrán", Buenos Aires, Argentina.
⁴ Laboratorio del Hospital Británico de Buenos Aires, Buenos Aires, Argentina.
⁵ Clinical and Environmental Microbiology Branch, Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.

PMID: 40465844
DOI: 10.1093/infdis/jiaf302

Abstract

Guiana Extended Spectrum (GES)-β-lactamase enzymes have been traditionally classified as extended-spectrum β-lactamases; however, there are increasing reports of GES variants with carbapenemase activity. This study reports the first characterization of GES-66, a GES-type not previously described, detected in a pair of sequence type 252 Klebsiella pneumoniae isolates from clinical and environmental sources in Argentina. GES-66 differs from GES-5 by a single amino acid substitution, E104K, while retaining the G170S alteration. Our data supports GES-66 has carbapenemase activity.

Keywords: Klebsiella pneumoniae; GES; GES-66; beta-lactamase; plasmid-mediated resistance.

© The Author(s) 2025. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.

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GES-66, Characterization of a new β-lactamase Gene Variant Detected in Klebsiella pneumoniae

Affiliations

GES-66, Characterization of a new β-lactamase Gene Variant Detected in Klebsiella pneumoniae

Authors

Affiliations

Abstract

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