In vitro activities of a novel nanoemulsion against Burkholderia and other multidrug-resistant cystic fibrosis-associated bacterial species

Antimicrob Agents Chemother. 2009 Jan;53(1):249-55. doi: 10.1128/AAC.00691-08. Epub 2008 Oct 27.


Respiratory tract infection, most often involving opportunistic bacterial species with broad-spectrum antibiotic resistance, is the primary cause of death in persons with cystic fibrosis (CF). Species within the Burkholderia cepacia complex are especially problematic in this patient population. We investigated a novel surfactant-stabilized oil-in-water nanoemulsion (NB-401) for activity against 150 bacterial isolates recovered primarily from CF respiratory tract specimens. These specimens included 75 Burkholderia isolates and 75 isolates belonging to other CF-relevant species including Pseudomonas, Achromobacter, Pandoraea, Ralstonia, Stenotrophomonas, and Acinetobacter. Nearly one-third of the isolates were multidrug resistant, and 20 (13%) were panresistant based on standard antibiotic testing. All isolates belonging to the same species were genotyped to ensure that each isolate was a distinct strain. The MIC(90) of NB-401 was 125 microg/ml. We found no decrease in activity against multidrug-resistant or panresistant strains. MBC testing showed no evidence of tolerance to NB-401. We investigated the activity of NB-401 against a subset of strains grown as a biofilm and against planktonic strains in the presence of CF sputum. Although the activity of NB-401 was decreased under both conditions, the nanoemulsion remained bactericidal for all strains tested. These results support NB-401's potential role as a novel antimicrobial agent for the treatment of infection due to CF-related opportunistic pathogens.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Biofilms / drug effects
  • Burkholderia / drug effects*
  • Burkholderia / isolation & purification
  • Cystic Fibrosis / microbiology*
  • Drug Resistance, Multiple, Bacterial
  • Emulsions / pharmacology*
  • Humans
  • Microbial Sensitivity Tests
  • Nanoparticles
  • Sputum / microbiology


  • Anti-Bacterial Agents
  • Emulsions