Outbreak of NDM-5-producing Klebsiella variicola in intensive care units: an overlooked pathogen in Argentina?

ABSTRACT Here, we characterized the first Klebsiella variicola isolates responsible for an outbreak in the intensive care units (ICUs) in a hospital in Argentina. Five isolates recovered from inpatients and sinks at the ICUs of one hospital in Bahia Blanca City were included. Identification and anti...

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Main Authors: Francisco González-Espinosa, Diego Marcelo Maurizi, Dina Pedersen, Alejandra Soledad Oriani, Celeste Martinez, Jerson Andrés Martínez Lozano, Gabriel Gutkind, Marcela Radice, Daniela Cejas
Format: Article
Language:English
Published: American Society for Microbiology 2025-08-01
Series:Microbiology Spectrum
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Online Access:https://journals.asm.org/doi/10.1128/spectrum.00672-25
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author Francisco González-Espinosa
Diego Marcelo Maurizi
Dina Pedersen
Alejandra Soledad Oriani
Celeste Martinez
Jerson Andrés Martínez Lozano
Gabriel Gutkind
Marcela Radice
Daniela Cejas
author_facet Francisco González-Espinosa
Diego Marcelo Maurizi
Dina Pedersen
Alejandra Soledad Oriani
Celeste Martinez
Jerson Andrés Martínez Lozano
Gabriel Gutkind
Marcela Radice
Daniela Cejas
author_sort Francisco González-Espinosa
collection DOAJ
description ABSTRACT Here, we characterized the first Klebsiella variicola isolates responsible for an outbreak in the intensive care units (ICUs) in a hospital in Argentina. Five isolates recovered from inpatients and sinks at the ICUs of one hospital in Bahia Blanca City were included. Identification and antimicrobial susceptibility tests were performed using an automated system (Phoenix). Besides, they were identified using two mass spectrometry systems (Bruker Daltonics and BioMérieux) and a multiplex-PCR for Klebsiella pneumoniae complex identification. Whole-genome sequencing (WGS) was conducted to confirm bacterial identification and to analyze their resistome and mobilome. Additionally, clonal and phylogenetic relationships were investigated among local and worldwide isolates. Based on the Phoenix system, all isolates were identified as K. pneumoniae and resistant to last-line antibiotics, consistent with a difficult-to-treat phenotype (DTR). All of them carried blaNDM-5. The isolates were identified as K. variicola by one of the Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) systems and by multiplex-PCR. WGS confirmed all isolates as K. variicola subsp. variicola belonging to ST3029, an infrequent lineage among the genomes analyzed. They displayed fewer than six SNPs, which corresponded to a unique clone, and the phylogenetic analysis exhibited a close relationship with isolates recovered from an environmental source in Brazil.IMPORTANCEKlebsiella variicola is an emerging pathogen in humans belonging to the K. pneumoniae complex. K. variicola identification by classical biochemical methods is challenging, and it is often misidentified as K. pneumoniae. K. variicola has been isolated from diverse clinical samples such as blood, respiratory, and urinary tract infections, and in different environments. The present work describes for the first time K. variicola isolates recovered in Argentina, which were resistant to the last line of antibiotics consistent with a difficult-to-treat phenotype and responsible for a hospital outbreak. In addition, the phylogenetic analysis exhibited a close relationship to environmental isolates from Brazil.
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spelling doaj-art-aadc5398042e47bebbd2e923bb825ed42025-08-20T02:56:43ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972025-08-0113810.1128/spectrum.00672-25Outbreak of NDM-5-producing Klebsiella variicola in intensive care units: an overlooked pathogen in Argentina?Francisco González-Espinosa0Diego Marcelo Maurizi1Dina Pedersen2Alejandra Soledad Oriani3Celeste Martinez4Jerson Andrés Martínez Lozano5Gabriel Gutkind6Marcela Radice7Daniela Cejas8Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Ciudad Autónoma de Buenos Aires, Buenos Aires, ArgentinaHospital Municipal Dr. Leónidas Lucero, Bahía Blanca, ArgentinaHospital Municipal Dr. Leónidas Lucero, Bahía Blanca, ArgentinaHospital Municipal Dr. Leónidas Lucero, Bahía Blanca, ArgentinaHospital Municipal Dr. Leónidas Lucero, Bahía Blanca, ArgentinaUniversidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Ciudad Autónoma de Buenos Aires, Buenos Aires, ArgentinaUniversidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Ciudad Autónoma de Buenos Aires, Buenos Aires, ArgentinaUniversidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Ciudad Autónoma de Buenos Aires, Buenos Aires, ArgentinaUniversidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Ciudad Autónoma de Buenos Aires, Buenos Aires, ArgentinaABSTRACT Here, we characterized the first Klebsiella variicola isolates responsible for an outbreak in the intensive care units (ICUs) in a hospital in Argentina. Five isolates recovered from inpatients and sinks at the ICUs of one hospital in Bahia Blanca City were included. Identification and antimicrobial susceptibility tests were performed using an automated system (Phoenix). Besides, they were identified using two mass spectrometry systems (Bruker Daltonics and BioMérieux) and a multiplex-PCR for Klebsiella pneumoniae complex identification. Whole-genome sequencing (WGS) was conducted to confirm bacterial identification and to analyze their resistome and mobilome. Additionally, clonal and phylogenetic relationships were investigated among local and worldwide isolates. Based on the Phoenix system, all isolates were identified as K. pneumoniae and resistant to last-line antibiotics, consistent with a difficult-to-treat phenotype (DTR). All of them carried blaNDM-5. The isolates were identified as K. variicola by one of the Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) systems and by multiplex-PCR. WGS confirmed all isolates as K. variicola subsp. variicola belonging to ST3029, an infrequent lineage among the genomes analyzed. They displayed fewer than six SNPs, which corresponded to a unique clone, and the phylogenetic analysis exhibited a close relationship with isolates recovered from an environmental source in Brazil.IMPORTANCEKlebsiella variicola is an emerging pathogen in humans belonging to the K. pneumoniae complex. K. variicola identification by classical biochemical methods is challenging, and it is often misidentified as K. pneumoniae. K. variicola has been isolated from diverse clinical samples such as blood, respiratory, and urinary tract infections, and in different environments. The present work describes for the first time K. variicola isolates recovered in Argentina, which were resistant to the last line of antibiotics consistent with a difficult-to-treat phenotype and responsible for a hospital outbreak. In addition, the phylogenetic analysis exhibited a close relationship to environmental isolates from Brazil.https://journals.asm.org/doi/10.1128/spectrum.00672-25Klebsiella variicolaoutbreakST3029ICUArgentinaIncHI1B-FIB
spellingShingle Francisco González-Espinosa
Diego Marcelo Maurizi
Dina Pedersen
Alejandra Soledad Oriani
Celeste Martinez
Jerson Andrés Martínez Lozano
Gabriel Gutkind
Marcela Radice
Daniela Cejas
Outbreak of NDM-5-producing Klebsiella variicola in intensive care units: an overlooked pathogen in Argentina?
Microbiology Spectrum
Klebsiella variicola
outbreak
ST3029
ICU
Argentina
IncHI1B-FIB
title Outbreak of NDM-5-producing Klebsiella variicola in intensive care units: an overlooked pathogen in Argentina?
title_full Outbreak of NDM-5-producing Klebsiella variicola in intensive care units: an overlooked pathogen in Argentina?
title_fullStr Outbreak of NDM-5-producing Klebsiella variicola in intensive care units: an overlooked pathogen in Argentina?
title_full_unstemmed Outbreak of NDM-5-producing Klebsiella variicola in intensive care units: an overlooked pathogen in Argentina?
title_short Outbreak of NDM-5-producing Klebsiella variicola in intensive care units: an overlooked pathogen in Argentina?
title_sort outbreak of ndm 5 producing klebsiella variicola in intensive care units an overlooked pathogen in argentina
topic Klebsiella variicola
outbreak
ST3029
ICU
Argentina
IncHI1B-FIB
url https://journals.asm.org/doi/10.1128/spectrum.00672-25
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