The evolution of TEM-1 extended-spectrum β-lactamases in E. coli by cephalosporins

Julie Clasen*, Anna Camilla Birkegård, Kaare Græsbøll, Anders Folkesson

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Objectives
This study was conducted to examine the molecular mechanisms responsible for evolution of TEM-type extended-spectrum β-lactamases (ESBLs), following selective pressure from four third-generation cephalosporins; ceftazidime, cefotaxime, ceftriaxone and ceftibuten. In addition, the approach selective enrichment for ESBL detection in environmental samples was investigated.

Methods
By the use of experimental evolution, resistant variants were isolated and mutations in TEM-1 were examined by DNA sequencing. Using E-tests and disc diffusion assays, resistance levels and development cross-resistance were determined for ESBL producers. Selective plating with or without prior growth in selective broth was used to examine the approach of selective enrichment for ESBL detection.

Results
The third-generation cephalosporins ceftazidime, cefotaxime and ceftriaxone selected for ESBL, while ceftibuten did not select for ESBL. All ESBL variants additionally remained susceptible towards ceftibuten. DNA sequencing of the TEM-1 coding sequence of mutants, revealed mutations that not previously had been isolated through selection. This indicates that the potential for ESBL evolution is much broader than can be inferred from sequence analysis of clinical samples alone.

Results: also indicate that selective enrichment for the enhanced detection of ESBL producers may give unreliable results due to the selection of spontaneous mutations in the narrow-spectrum β-lactamases such as TEM-type ESBL producers.

Conclusions
These results help explain the molecular changes responsible for evolution of TEM-type ESBLs, meanwhile question the appropriate use of selective enrichment for detection of ESBLs in environmental samples.
Original languageEnglish
JournalJournal of Global Antimicrobial Resistance
Volume19
Pages (from-to)32-39
ISSN2213-7165
DOIs
Publication statusPublished - 2019

Keywords

  • Escherichia coli
  • Extended-spectrum-beta-lactamases
  • Antimicrobial resistance
  • Evolution
  • Third generation cephalosporins

Cite this

@article{6f754629edd240a7adf96e02e08aff4f,
title = "The evolution of TEM-1 extended-spectrum β-lactamases in E. coli by cephalosporins",
abstract = "ObjectivesThis study was conducted to examine the molecular mechanisms responsible for evolution of TEM-type extended-spectrum β-lactamases (ESBLs), following selective pressure from four third-generation cephalosporins; ceftazidime, cefotaxime, ceftriaxone and ceftibuten. In addition, the approach selective enrichment for ESBL detection in environmental samples was investigated.MethodsBy the use of experimental evolution, resistant variants were isolated and mutations in TEM-1 were examined by DNA sequencing. Using E-tests and disc diffusion assays, resistance levels and development cross-resistance were determined for ESBL producers. Selective plating with or without prior growth in selective broth was used to examine the approach of selective enrichment for ESBL detection.ResultsThe third-generation cephalosporins ceftazidime, cefotaxime and ceftriaxone selected for ESBL, while ceftibuten did not select for ESBL. All ESBL variants additionally remained susceptible towards ceftibuten. DNA sequencing of the TEM-1 coding sequence of mutants, revealed mutations that not previously had been isolated through selection. This indicates that the potential for ESBL evolution is much broader than can be inferred from sequence analysis of clinical samples alone.Results: also indicate that selective enrichment for the enhanced detection of ESBL producers may give unreliable results due to the selection of spontaneous mutations in the narrow-spectrum β-lactamases such as TEM-type ESBL producers.ConclusionsThese results help explain the molecular changes responsible for evolution of TEM-type ESBLs, meanwhile question the appropriate use of selective enrichment for detection of ESBLs in environmental samples.",
keywords = "Escherichia coli, Extended-spectrum-beta-lactamases, Antimicrobial resistance, Evolution, Third generation cephalosporins",
author = "Julie Clasen and Birkeg{\aa}rd, {Anna Camilla} and Kaare Gr{\ae}sb{\o}ll and Anders Folkesson",
year = "2019",
doi = "10.1016/j.jgar.2019.03.010",
language = "English",
volume = "19",
pages = "32--39",
journal = "Journal of Global Antimicrobial Resistance",
issn = "2213-7165",
publisher = "Elsevier",

}

The evolution of TEM-1 extended-spectrum β-lactamases in E. coli by cephalosporins. / Clasen, Julie; Birkegård, Anna Camilla; Græsbøll, Kaare; Folkesson, Anders.

In: Journal of Global Antimicrobial Resistance, Vol. 19, 2019, p. 32-39.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - The evolution of TEM-1 extended-spectrum β-lactamases in E. coli by cephalosporins

AU - Clasen, Julie

AU - Birkegård, Anna Camilla

AU - Græsbøll, Kaare

AU - Folkesson, Anders

PY - 2019

Y1 - 2019

N2 - ObjectivesThis study was conducted to examine the molecular mechanisms responsible for evolution of TEM-type extended-spectrum β-lactamases (ESBLs), following selective pressure from four third-generation cephalosporins; ceftazidime, cefotaxime, ceftriaxone and ceftibuten. In addition, the approach selective enrichment for ESBL detection in environmental samples was investigated.MethodsBy the use of experimental evolution, resistant variants were isolated and mutations in TEM-1 were examined by DNA sequencing. Using E-tests and disc diffusion assays, resistance levels and development cross-resistance were determined for ESBL producers. Selective plating with or without prior growth in selective broth was used to examine the approach of selective enrichment for ESBL detection.ResultsThe third-generation cephalosporins ceftazidime, cefotaxime and ceftriaxone selected for ESBL, while ceftibuten did not select for ESBL. All ESBL variants additionally remained susceptible towards ceftibuten. DNA sequencing of the TEM-1 coding sequence of mutants, revealed mutations that not previously had been isolated through selection. This indicates that the potential for ESBL evolution is much broader than can be inferred from sequence analysis of clinical samples alone.Results: also indicate that selective enrichment for the enhanced detection of ESBL producers may give unreliable results due to the selection of spontaneous mutations in the narrow-spectrum β-lactamases such as TEM-type ESBL producers.ConclusionsThese results help explain the molecular changes responsible for evolution of TEM-type ESBLs, meanwhile question the appropriate use of selective enrichment for detection of ESBLs in environmental samples.

AB - ObjectivesThis study was conducted to examine the molecular mechanisms responsible for evolution of TEM-type extended-spectrum β-lactamases (ESBLs), following selective pressure from four third-generation cephalosporins; ceftazidime, cefotaxime, ceftriaxone and ceftibuten. In addition, the approach selective enrichment for ESBL detection in environmental samples was investigated.MethodsBy the use of experimental evolution, resistant variants were isolated and mutations in TEM-1 were examined by DNA sequencing. Using E-tests and disc diffusion assays, resistance levels and development cross-resistance were determined for ESBL producers. Selective plating with or without prior growth in selective broth was used to examine the approach of selective enrichment for ESBL detection.ResultsThe third-generation cephalosporins ceftazidime, cefotaxime and ceftriaxone selected for ESBL, while ceftibuten did not select for ESBL. All ESBL variants additionally remained susceptible towards ceftibuten. DNA sequencing of the TEM-1 coding sequence of mutants, revealed mutations that not previously had been isolated through selection. This indicates that the potential for ESBL evolution is much broader than can be inferred from sequence analysis of clinical samples alone.Results: also indicate that selective enrichment for the enhanced detection of ESBL producers may give unreliable results due to the selection of spontaneous mutations in the narrow-spectrum β-lactamases such as TEM-type ESBL producers.ConclusionsThese results help explain the molecular changes responsible for evolution of TEM-type ESBLs, meanwhile question the appropriate use of selective enrichment for detection of ESBLs in environmental samples.

KW - Escherichia coli

KW - Extended-spectrum-beta-lactamases

KW - Antimicrobial resistance

KW - Evolution

KW - Third generation cephalosporins

U2 - 10.1016/j.jgar.2019.03.010

DO - 10.1016/j.jgar.2019.03.010

M3 - Journal article

C2 - 31048029

VL - 19

SP - 32

EP - 39

JO - Journal of Global Antimicrobial Resistance

JF - Journal of Global Antimicrobial Resistance

SN - 2213-7165

ER -