The exclusion of dead bacterial cells is essential for accurate molecular analysis of clinical samples

Clin Microbiol Infect. 2010 Nov;16(11):1656-8. doi: 10.1111/j.1469-0691.2010.03189.x.


The DNA-based techniques used to detect bacteria in clinical samples are unable to discriminate between live bacteria, dead bacteria, and extracellular DNA. This failure to limit analysis to viable bacterial cells represents a significant problem, leading to false-positive results, as well as a failure to resolve the impact of antimicrobial therapy. The use of propidium monoazide treatment significantly reduces the contribution of dead cells and extracellular DNA to such culture-independent analyses. Here, the increased ability to resolve the impact of antibiotic therapy on Pseudomonas aeruginosa load in cystic fibrosis respiratory samples reveals statistically significant changes that would otherwise go undetected.

MeSH terms

  • Adult
  • Anti-Bacterial Agents / therapeutic use*
  • Azides*
  • Cystic Fibrosis / complications
  • Cystic Fibrosis / microbiology
  • DNA, Bacterial / analysis
  • DNA, Bacterial / genetics
  • False Positive Reactions
  • Gene Expression Profiling
  • Humans
  • Intercalating Agents / chemistry
  • Microbial Viability*
  • Polymerase Chain Reaction / methods*
  • Propidium / analogs & derivatives*
  • Pseudomonas Infections / complications
  • Pseudomonas Infections / drug therapy*
  • Pseudomonas Infections / microbiology
  • Pseudomonas aeruginosa / genetics
  • Pseudomonas aeruginosa / isolation & purification*
  • Pseudomonas aeruginosa / physiology


  • Anti-Bacterial Agents
  • Azides
  • DNA, Bacterial
  • Intercalating Agents
  • propidium monoazide
  • Propidium