Investigating the role of matrix components in protection of Burkholderia cepacia complex biofilms against tobramycin

Background: Burkholderia cepacia complex (Bcc) organisms produce a wide variety of potential virulence factors, including exopolysaccharides (BPS), and exhibit intrinsic resistance towards many antibiotics. In the present study we investigated the contribution of Bcc biofilm matrix components, including extacellular DNA, cepacian and poly-beta-1,6-N-acetylglucosamine, to tobramycin susceptibility. Methods: The in vitro bactericidal activity of tobramycin in combination with recombinant human DNase (rhDNase), NaClO and dispersin B was tested against Bcc biofilms. Results: EPS degradation by NaClO pretreatment and specific PNAG degradation by dispersin B significantly increased the bactericidal effect of tobramycin towards some of the Bcc biofilms tested, including the strain's of Burkholderia cenocepacia, B. cepacia and Burkholderia metallica. The presence of rhDNase during biofilm treatment and/or development had no influence on tobramycin activity. Conclusion: These results suggest that BPS play a role in tobramycin susceptibility of Bcc biofilms and that matrix degrading combination therapy could improve treatment of Bcc biofilm infections. (C) 2013 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.