Molecular characterization of extended-spectrum β-lactamase-producing Escherichia coli isolated from lower respiratory tract samples between 2002 and 2019 in the Central Slovenia region

Abstract Background Antibiotic resistance is one of the most serious global health problems and threatens the effective treatment of bacterial infections. Of greatest concern are infections caused by extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC). The aim of our study was to eval...

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Main Authors: Katja Hrovat, Katja Molan, Katja Seme, Jerneja Ambrožič Avguštin
Format: Article
Language:English
Published: BMC 2024-01-01
Series:Annals of Clinical Microbiology and Antimicrobials
Subjects:
Online Access:https://doi.org/10.1186/s12941-023-00664-1
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author Katja Hrovat
Katja Molan
Katja Seme
Jerneja Ambrožič Avguštin
author_facet Katja Hrovat
Katja Molan
Katja Seme
Jerneja Ambrožič Avguštin
author_sort Katja Hrovat
collection DOAJ
description Abstract Background Antibiotic resistance is one of the most serious global health problems and threatens the effective treatment of bacterial infections. Of greatest concern are infections caused by extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC). The aim of our study was to evaluate the prevalence and molecular characteristics of ESBL-EC isolated over an 18-year pre-COVID period from lower respiratory tract (LRT) samples collected from selected Slovenian hospitals. Objectives and methods All isolates were identified by MALDI-TOF and phenotypically confirmed as ESBLs by a disk diffusion assay. Using a PCR approach, 487 non-repetitive isolates were assigned to phylogroups, sequence type groups, and clonal groups. Isolates were also screened for virulence-associated genes (VAGs) and antimicrobial resistance genes. Results The prevalence of ESBL-EC isolates from LRT in a large university hospital was low (1.4%) in 2005 and increased to 10.8% by 2019. The resistance profile of 487 non-repetitive isolates included in the study showed a high frequency of group 1 bla CTX-M (77.4%; n = 377), bla TEM (54.4%; n = 265) and aac(6')-Ib-cr (52%; n = 253) genes and a low proportion of bla SHV and qnr genes. Isolates were predominantly assigned to phylogroup B2 (73.1%; n = 356), which was significantly associated with clonal group ST131. The ST131 group accounted for 67.6% (n = 329) of all isolates and had a higher number of virulence factor genes than the non-ST131 group. The virulence gene profile of ST131 was consistent with that of other extraintestinal pathogenic E. coli (ExPEC) strains and was significantly associated with ten of sixteen virulence factor genes tested. Using ERIC-PCR fingerprinting, isolates with the same ERIC-profile in samples from different patients, and at different locations and sampling dates were confirmed, indicating the presence of “hospital-adapted” strains. Conclusion Our results suggest that the ESBL-EC isolates from LRT do not represent a specific pathotype, but rather resemble other ExPEC isolates, and may be adapted to the hospital environment. To our knowledge, this is the first study of ESBL-EC isolated from LRT samples collected over a long period of time.
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spelling doaj.art-d427f4197b134f9ea3ded93a963efd4d2024-01-14T12:15:07ZengBMCAnnals of Clinical Microbiology and Antimicrobials1476-07112024-01-0123111310.1186/s12941-023-00664-1Molecular characterization of extended-spectrum β-lactamase-producing Escherichia coli isolated from lower respiratory tract samples between 2002 and 2019 in the Central Slovenia regionKatja Hrovat0Katja Molan1Katja Seme2Jerneja Ambrožič Avguštin3Department of Biology, Biotechnical Faculty, University of LjubljanaDepartment of Microbiology, Biotechnical Faculty, University of LjubljanaInstitute of Microbiology and Immunology, Faculty of Medicine, University of LjubljanaDepartment of Biology, Biotechnical Faculty, University of LjubljanaAbstract Background Antibiotic resistance is one of the most serious global health problems and threatens the effective treatment of bacterial infections. Of greatest concern are infections caused by extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC). The aim of our study was to evaluate the prevalence and molecular characteristics of ESBL-EC isolated over an 18-year pre-COVID period from lower respiratory tract (LRT) samples collected from selected Slovenian hospitals. Objectives and methods All isolates were identified by MALDI-TOF and phenotypically confirmed as ESBLs by a disk diffusion assay. Using a PCR approach, 487 non-repetitive isolates were assigned to phylogroups, sequence type groups, and clonal groups. Isolates were also screened for virulence-associated genes (VAGs) and antimicrobial resistance genes. Results The prevalence of ESBL-EC isolates from LRT in a large university hospital was low (1.4%) in 2005 and increased to 10.8% by 2019. The resistance profile of 487 non-repetitive isolates included in the study showed a high frequency of group 1 bla CTX-M (77.4%; n = 377), bla TEM (54.4%; n = 265) and aac(6')-Ib-cr (52%; n = 253) genes and a low proportion of bla SHV and qnr genes. Isolates were predominantly assigned to phylogroup B2 (73.1%; n = 356), which was significantly associated with clonal group ST131. The ST131 group accounted for 67.6% (n = 329) of all isolates and had a higher number of virulence factor genes than the non-ST131 group. The virulence gene profile of ST131 was consistent with that of other extraintestinal pathogenic E. coli (ExPEC) strains and was significantly associated with ten of sixteen virulence factor genes tested. Using ERIC-PCR fingerprinting, isolates with the same ERIC-profile in samples from different patients, and at different locations and sampling dates were confirmed, indicating the presence of “hospital-adapted” strains. Conclusion Our results suggest that the ESBL-EC isolates from LRT do not represent a specific pathotype, but rather resemble other ExPEC isolates, and may be adapted to the hospital environment. To our knowledge, this is the first study of ESBL-EC isolated from LRT samples collected over a long period of time.https://doi.org/10.1186/s12941-023-00664-1Escherichia coliLower respiratory tractExtended-spectrum β-lactamaseAntibiotic resistanceST131Virulence factors
spellingShingle Katja Hrovat
Katja Molan
Katja Seme
Jerneja Ambrožič Avguštin
Molecular characterization of extended-spectrum β-lactamase-producing Escherichia coli isolated from lower respiratory tract samples between 2002 and 2019 in the Central Slovenia region
Annals of Clinical Microbiology and Antimicrobials
Escherichia coli
Lower respiratory tract
Extended-spectrum β-lactamase
Antibiotic resistance
ST131
Virulence factors
title Molecular characterization of extended-spectrum β-lactamase-producing Escherichia coli isolated from lower respiratory tract samples between 2002 and 2019 in the Central Slovenia region
title_full Molecular characterization of extended-spectrum β-lactamase-producing Escherichia coli isolated from lower respiratory tract samples between 2002 and 2019 in the Central Slovenia region
title_fullStr Molecular characterization of extended-spectrum β-lactamase-producing Escherichia coli isolated from lower respiratory tract samples between 2002 and 2019 in the Central Slovenia region
title_full_unstemmed Molecular characterization of extended-spectrum β-lactamase-producing Escherichia coli isolated from lower respiratory tract samples between 2002 and 2019 in the Central Slovenia region
title_short Molecular characterization of extended-spectrum β-lactamase-producing Escherichia coli isolated from lower respiratory tract samples between 2002 and 2019 in the Central Slovenia region
title_sort molecular characterization of extended spectrum β lactamase producing escherichia coli isolated from lower respiratory tract samples between 2002 and 2019 in the central slovenia region
topic Escherichia coli
Lower respiratory tract
Extended-spectrum β-lactamase
Antibiotic resistance
ST131
Virulence factors
url https://doi.org/10.1186/s12941-023-00664-1
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