Killing effect of nanoencapsulated colistin sulfate on Pseudomonas aeruginosa from cystic fibrosis patients

J Cyst Fibros. 2016 Sep;15(5):611-8. doi: 10.1016/j.jcf.2015.12.005. Epub 2015 Dec 18.

Abstract

Pseudomonas aeruginosa frequently infects the respiratory tract of cystic fibrosis (CF) patients. Multidrug-resistant phenotypes and high capacity to form stable biofilms are common. Recent studies have described the emergence of colistin-resistant isolates in CF patients treated with long-term inhaled colistin. The use of nanoparticles containing antimicrobials can contribute to overcome drug resistance mechanisms. The aim of this study was to explore antimicrobial activity of nanoencapsulated colistin (SLN-NLC) versus free colistin against P. aeruginosa clinical isolates from CF patients and to investigate their efficacy in biofilm eradication. Susceptibility of planktonic bacteria to antimicrobials was examined by using the broth microdilution method and growth curve assay. Minimal biofilm eradication concentration (MBEC) and biofilm prevention concentration (BPC) were determined to assess antimicrobial susceptibility of sessile bacteria. We used atomic force microscopy (AFM) to visualize treated and untreated biofilms and to determine surface roughness and other relevant parameters. Colistin nanoparticles had the same antimicrobial activity as free drug against planktonic bacteria. However, nanoencapsulated colistin was much more efficient in the eradication of biofilms than free colistin. Thus, these formulations have to be considered as a good alternative therapeutic option to treat P. aeruginosa infections.

Keywords: Antimicrobial effect; Colistin sulfate; Cystic fibrosis; Lipid nanoparticles; Pseudomonas aeruginosa.

MeSH terms

  • Adult
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / pharmacokinetics
  • Biofilms / drug effects*
  • Child
  • Colistin* / administration & dosage
  • Colistin* / pharmacokinetics
  • Cystic Fibrosis* / diagnosis
  • Cystic Fibrosis* / epidemiology
  • Cystic Fibrosis* / microbiology
  • Cystic Fibrosis* / therapy
  • Drug Delivery Systems / methods
  • Drug Monitoring / methods
  • Drug Resistance, Bacterial / drug effects
  • Female
  • Humans
  • Male
  • Middle Aged
  • Nanoparticles / administration & dosage
  • Outcome Assessment, Health Care
  • Pseudomonas Infections* / diagnosis
  • Pseudomonas Infections* / drug therapy
  • Pseudomonas aeruginosa* / drug effects
  • Pseudomonas aeruginosa* / isolation & purification
  • Pseudomonas aeruginosa* / physiology
  • Respiratory System / microbiology
  • Respiratory Tract Infections* / diagnosis
  • Respiratory Tract Infections* / drug therapy
  • Respiratory Tract Infections* / microbiology
  • Spain / epidemiology

Substances

  • Anti-Bacterial Agents
  • Colistin