Phenotypic and genomic changes in enteric Klebsiella populations during long-term ICU patient hospitalization: the role of RamR regulation

ABSTRACT Acquired antimicrobial resistance and metabolic changes are central for bacterial host adaptation during the long-term hospitalization of patients. We aimed to analyze the genomic and phenotypic evolution of enteric Klebsiella populations in long-term intensive care unit (ICU) patients. Wee...

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Main Authors: Benedicte Langlois, Francois Guerin, Christophe Isnard, Clement Gakuba, Damien Du Cheyron, Jean-Christophe Giard, Sylvain Brisse, Simon Le Hello, Francois Gravey
Format: Article
Language:English
Published: American Society for Microbiology 2024-12-01
Series:mSphere
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Online Access:https://journals.asm.org/doi/10.1128/msphere.00704-24
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author Benedicte Langlois
Francois Guerin
Christophe Isnard
Clement Gakuba
Damien Du Cheyron
Jean-Christophe Giard
Sylvain Brisse
Simon Le Hello
Francois Gravey
author_facet Benedicte Langlois
Francois Guerin
Christophe Isnard
Clement Gakuba
Damien Du Cheyron
Jean-Christophe Giard
Sylvain Brisse
Simon Le Hello
Francois Gravey
author_sort Benedicte Langlois
collection DOAJ
description ABSTRACT Acquired antimicrobial resistance and metabolic changes are central for bacterial host adaptation during the long-term hospitalization of patients. We aimed to analyze the genomic and phenotypic evolution of enteric Klebsiella populations in long-term intensive care unit (ICU) patients. Weekly rectal swabs were prospectively collected from all patients admitted to the ICU in a teaching hospital from December 2018 to February 2019. The inclusion criterion for patients was hospitalization for more than 15 days in the ICU without any history of hospitalization or antibiotic treatment for the 3 months prior to admission. Among them, enteric Klebsiella pneumoniae species complex (KpSC) populations were detected. For each isolate, extensive antimicrobial resistance profiles were determined using the disk diffusion method, and the whole genome was sequenced using an Illumina platform. In silico typing methods, such as Multilocus Sequence Typing (MLST), core-genome MLST, SNP typing, resistome characterization and mutation point detection, were applied. During the study period, 471 patients were admitted to ICUs. Among them, 21 patients met the inclusion criteria, and only 5 patients (24%) carried unique and distinct KpSC populations during 2–10 weeks in the gut that as detected at admission and excluding acquisition during the ICU stay. One patient showed a rare ST1563 K. variicola persistent carriage for 7 consecutive weeks, which displayed important antimicrobial resistance phenotype changes in the 2 last weeks. In-depth in silico characterization and RNA sequencing of these strains revealed a mutation within the ramR transcriptional regulator resulting in overexpression of the ramA regulator and decreased expression of acrR, which controls antibiotic efflux. This mutation also impacts tolerance to biliary salts. This study revealed the importance of endogenous colonization of KpSC populations in the gut throughout the patient’s long-term ICU stay and highlighted the role of ramR in drug susceptibility.IMPORTANCEThe Klebsiella pneumoniae species complex (KpSC) is one of the major causes of nosocomial infections, especially in intensive care unit (ICUs). These bacteria are frequently highly resistant to antibiotics, leading to an increase in morbidity and mortality. The origins of multidrug-resistant KpSC strains isolated from ICU patients are still unclear, with at least two hypotheses of acquisition paths: (i) endogenous KpSC populations that are or became resistant to antibiotics and/or (ii) hospital acquisition of circulating KpSC clones. Genomic changes observed in this study might reveal mechanisms to better adapt to KpSC in the patient’s gut in the face of heavy ICU medical care pressure.
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spelling doaj-art-965e059724f7499d8558418cee7a21642025-08-20T02:52:30ZengAmerican Society for MicrobiologymSphere2379-50422024-12-0191210.1128/msphere.00704-24Phenotypic and genomic changes in enteric Klebsiella populations during long-term ICU patient hospitalization: the role of RamR regulationBenedicte Langlois0Francois Guerin1Christophe Isnard2Clement Gakuba3Damien Du Cheyron4Jean-Christophe Giard5Sylvain Brisse6Simon Le Hello7Francois Gravey8Univ de Caen Normandie, Univ Rouen Normandie, INSERM, DYNAMICURE, Caen, FranceUniv de Caen Normandie, Univ Rouen Normandie, INSERM, DYNAMICURE, Caen, FranceUniv de Caen Normandie, Univ Rouen Normandie, INSERM, DYNAMICURE, Caen, FranceDepartment of Surgical Intensive Care, CHU Caen, Caen, FranceDepartment of Medical Intensive Care, CHU Caen, Caen, FranceUniv de Caen Normandie, Univ Rouen Normandie, INSERM, DYNAMICURE, Caen, FranceInstitut Pasteur, Université Paris Cité, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, FranceUniv de Caen Normandie, Univ Rouen Normandie, INSERM, DYNAMICURE, Caen, FranceUniv de Caen Normandie, Univ Rouen Normandie, INSERM, DYNAMICURE, Caen, FranceABSTRACT Acquired antimicrobial resistance and metabolic changes are central for bacterial host adaptation during the long-term hospitalization of patients. We aimed to analyze the genomic and phenotypic evolution of enteric Klebsiella populations in long-term intensive care unit (ICU) patients. Weekly rectal swabs were prospectively collected from all patients admitted to the ICU in a teaching hospital from December 2018 to February 2019. The inclusion criterion for patients was hospitalization for more than 15 days in the ICU without any history of hospitalization or antibiotic treatment for the 3 months prior to admission. Among them, enteric Klebsiella pneumoniae species complex (KpSC) populations were detected. For each isolate, extensive antimicrobial resistance profiles were determined using the disk diffusion method, and the whole genome was sequenced using an Illumina platform. In silico typing methods, such as Multilocus Sequence Typing (MLST), core-genome MLST, SNP typing, resistome characterization and mutation point detection, were applied. During the study period, 471 patients were admitted to ICUs. Among them, 21 patients met the inclusion criteria, and only 5 patients (24%) carried unique and distinct KpSC populations during 2–10 weeks in the gut that as detected at admission and excluding acquisition during the ICU stay. One patient showed a rare ST1563 K. variicola persistent carriage for 7 consecutive weeks, which displayed important antimicrobial resistance phenotype changes in the 2 last weeks. In-depth in silico characterization and RNA sequencing of these strains revealed a mutation within the ramR transcriptional regulator resulting in overexpression of the ramA regulator and decreased expression of acrR, which controls antibiotic efflux. This mutation also impacts tolerance to biliary salts. This study revealed the importance of endogenous colonization of KpSC populations in the gut throughout the patient’s long-term ICU stay and highlighted the role of ramR in drug susceptibility.IMPORTANCEThe Klebsiella pneumoniae species complex (KpSC) is one of the major causes of nosocomial infections, especially in intensive care unit (ICUs). These bacteria are frequently highly resistant to antibiotics, leading to an increase in morbidity and mortality. The origins of multidrug-resistant KpSC strains isolated from ICU patients are still unclear, with at least two hypotheses of acquisition paths: (i) endogenous KpSC populations that are or became resistant to antibiotics and/or (ii) hospital acquisition of circulating KpSC clones. Genomic changes observed in this study might reveal mechanisms to better adapt to KpSC in the patient’s gut in the face of heavy ICU medical care pressure.https://journals.asm.org/doi/10.1128/msphere.00704-24Klebsiella variicolalong-term carriageintensive care unitspopulation dynamicRamRhost adaptation
spellingShingle Benedicte Langlois
Francois Guerin
Christophe Isnard
Clement Gakuba
Damien Du Cheyron
Jean-Christophe Giard
Sylvain Brisse
Simon Le Hello
Francois Gravey
Phenotypic and genomic changes in enteric Klebsiella populations during long-term ICU patient hospitalization: the role of RamR regulation
mSphere
Klebsiella variicola
long-term carriage
intensive care units
population dynamic
RamR
host adaptation
title Phenotypic and genomic changes in enteric Klebsiella populations during long-term ICU patient hospitalization: the role of RamR regulation
title_full Phenotypic and genomic changes in enteric Klebsiella populations during long-term ICU patient hospitalization: the role of RamR regulation
title_fullStr Phenotypic and genomic changes in enteric Klebsiella populations during long-term ICU patient hospitalization: the role of RamR regulation
title_full_unstemmed Phenotypic and genomic changes in enteric Klebsiella populations during long-term ICU patient hospitalization: the role of RamR regulation
title_short Phenotypic and genomic changes in enteric Klebsiella populations during long-term ICU patient hospitalization: the role of RamR regulation
title_sort phenotypic and genomic changes in enteric klebsiella populations during long term icu patient hospitalization the role of ramr regulation
topic Klebsiella variicola
long-term carriage
intensive care units
population dynamic
RamR
host adaptation
url https://journals.asm.org/doi/10.1128/msphere.00704-24
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