The antibacterial properties of docosahexaenoic omega-3 fatty acid against the cystic fibrosis multiresistant pathogen Burkholderia cenocepacia

Authors

  • Dalila Mil-Homens,

    1. IBB-Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
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  • Nuno Bernardes,

    1. IBB-Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
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  • Arsénio M. Fialho

    Corresponding author
    1. Department of Bioengineering, Instituto Superior Técnico, Technical University of Lisbon, Lisbon, Portugal
    • IBB-Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
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Correspondence: Arsénio M. Fialho, IBB-Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon 1049-001, Portugal. Tel.: +351 21 8417684; fax: +351 21 8419199; e-mail: afialho@ist.utl.pt

Abstract

Burkholderia cepacia complex (Bcc) bacteria are opportunistic pathogens that cause multiresistant pulmonary infections in patients with cystic fibrosis (CF). In this study, we evaluated the in vitro antimicrobial efficacy of eight unsaturated fatty acids against Burkholderia cenocepacia K56-2, a CF epidemic strain. Docosahexaenoic acid (DHA) was the most active compound. Its action can be either bacteriostatic or bactericidal, depending upon the concentration used. The effect of DHA was also evaluated on two others B. cenocepacia clinical isolates and compared with one representative member of all the 17 Bcc species. To test whether DHA could have a therapeutic potential, we assessed its efficacy using a Galleria mellonella caterpillar model of B. cenocepacia infection. We observed that the treatment of infected larvae with a single dose of DHA (50 mM) caused an increase in the survival rate as well as a reduced bacterial load. Moreover, DHA administration markedly increases the expression profile of the gene encoding the antimicrobial peptide gallerimycin. Our results demonstrate that DHA has in vitro and in vivo antibacterial activity against Bcc microorganisms. These findings provide evidence that DHA may be a useful nutraceutical for the treatment of CF patients with lung infections caused by antibiotic multiresistant Bcc microorganisms.

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