Detection of volatile compounds emitted by Pseudomonas aeruginosa using selected ion flow tube mass spectrometry.
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.
Carroll
Will
W
Academic Department of Paediatrics, University Hospital of North Staffordshire, Stoke-on-Trent, UK.
Lenney
Warren
W
Wang
Tianshu
T
Spanel
Patrik
P
Alcock
Alice
A
Smith
David
D
D000097:Acetonitriles / Q000032:analysis; D000293:Adolescent; D000328:Adult; D000641:Ammonia / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D003371:Cough / Q000382:microbiology; D003470:Culture Media; D003550:Cystic Fibrosis / Q000382:microbiology; D004220:Disulfides / Q000032:analysis; D005240:Feasibility Studies; D006801:Humans; D006856:Hydrogen Cyanide / Q000032:analysis; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D009812:Odorants / Q000032:analysis*; D011552:Pseudomonas Infections / Q000175:diagnosis; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D013438:Sulfhydryl Compounds / Q000032:analysis
D000097:Acetonitriles; D015415:Biomarkers; D003470:Culture Media; D004220:Disulfides; D013438:Sulfhydryl Compounds; D006856:Hydrogen Cyanide; C005231:methylmercaptan; C021181:dimethyl disulfide; D000641:Ammonia; C032159:acetonitrile