Evaluation of the electron transfer flavoprotein as an antibacterial target in Burkholderia cenocepacia

Can J Microbiol. 2017 Oct;63(10):857-863. doi: 10.1139/cjm-2017-0350. Epub 2017 Aug 17.


There are hundreds of essential genes in multidrug-resistant bacterial genomes, but only a few of their products are exploited as antibacterial targets. An example is the electron transfer flavoprotein (ETF), which is required for growth and viability in Burkholderia cenocepacia. Here, we evaluated ETF as an antibiotic target for Burkholderia cepacia complex (Bcc). Depletion of the bacterial ETF during infection of Caenorhabditis elegans significantly extended survival of the nematodes, proving that ETF is essential for survival of B. cenocepacia in this host model. In spite of the arrest in respiration in ETF mutants, the inhibition of etf expression did not increase the formation of persister cells, when treated with high doses of ciprofloxacin or meropenem. To test if etf translation could be inhibited by RNA interference, antisense oligonucleotides that target the etfBA operon were synthesized. One antisense oligonucleotide was effective in inhibiting etfB translation in vitro but not in vivo, highlighting the challenge of reduced membrane permeability for the design of drugs against B. cenocepacia. This work contributes to the validation of ETF of B. cenocepacia as a target for antibacterial therapy and demonstrates the utility of a C. elegans liquid killing assay to validate gene essentiality in an in vivo infection model.

Keywords: Burkholderia cenocepacia; Caenorhabditis elegans; antibacterial targets; antisense oligonucleotides; cellules persistantes dormantes; cibles antibactériennes; cystic fibrosis; electron transfer flavoprotein (ETF); essential genes; fibrose kystique; flavoprotéine de transfert d’électrons (ETF); gènes essentiels; oligonucléotides antisens; persister cells.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Burkholderia cenocepacia / genetics*
  • Burkholderia cenocepacia / physiology
  • Caenorhabditis elegans / microbiology*
  • Caenorhabditis elegans / physiology
  • Cell Membrane Permeability
  • Ciprofloxacin / pharmacology
  • Electron-Transferring Flavoproteins / genetics*
  • Electron-Transferring Flavoproteins / metabolism
  • Meropenem
  • Mutation
  • Oligonucleotides, Antisense / genetics
  • RNA Interference
  • Thienamycins / pharmacology


  • Anti-Bacterial Agents
  • Electron-Transferring Flavoproteins
  • Oligonucleotides, Antisense
  • Thienamycins
  • Ciprofloxacin
  • Meropenem