Detection of volatile compounds emitted by Pseudomonas aeruginosa using selected ion flow tube mass spectrometry

Pediatr Pulmonol. 2005 May;39(5):452-6. doi: 10.1002/ppul.20170.


Pseudomonas aeruginosa (PA) is associated with a distinctive smell produced by a combination of volatile compounds (VCs). Selected ion flow tube mass spectrometry (SIFT-MS) provides a novel and rapid methodology for rapid, accurate detection of trace quantities (parts per billion; ppb) of VCs in air. We studied the VCs produced by different isolates of PA cultures in vitro from patients with cystic fibrosis. Twenty-one patients with cystic fibrosis provided sputum and cough swab samples for culture. These were used to inoculate blood agar (BA) and Pseudomonas-selective media (PSM). These plates were incubated for 48 hr at 37 degrees C inside sealed plastic bags. The air surrounding the samples after 48 hr (headspace) was analyzed using SIFT-MS. PA growth was commonly associated with the production of significant quantities of VCs, notably hydrogen cyanide gas (HCN). This was detectable in the headspace of 15/22 of PA-positive samples. In contrast, it was only seen in the headspace of 1/13 control samples (6 sterile plates and 7 plates with only mixed upper respiratory tract flora). The concentration of HCN was significantly higher above PA-positive samples than above other bacterial growth (P < 0.01), and in our study, levels of HCN greater than 100 ppb were a sensitive (68%) and highly specific (100%) biomarker of PA. SIFT-MS can detect a range of VCs from PA in vitro. HCN may be a specific indicator of PA infection in vivo, and offers promise as a biomarker for noninvasive detection of PA infection by breath analysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetonitriles / analysis
  • Adolescent
  • Adult
  • Ammonia / analysis
  • Biomarkers / analysis
  • Child
  • Child, Preschool
  • Cough / microbiology
  • Culture Media
  • Cystic Fibrosis / microbiology
  • Disulfides / analysis
  • Feasibility Studies
  • Humans
  • Hydrogen Cyanide / analysis
  • Mass Spectrometry / instrumentation
  • Mass Spectrometry / methods
  • Odorants / analysis*
  • Pseudomonas Infections / diagnosis
  • Pseudomonas aeruginosa / metabolism*
  • Sensitivity and Specificity
  • Sputum / microbiology
  • Sulfhydryl Compounds / analysis


  • Acetonitriles
  • Biomarkers
  • Culture Media
  • Disulfides
  • Sulfhydryl Compounds
  • Hydrogen Cyanide
  • methylmercaptan
  • dimethyl disulfide
  • Ammonia
  • acetonitrile