title: Identification of airway bacterial colonization by an electronic nose in Chronic Obstructive Pulmonary Disease.
abstract: BACKGROUND
  Airway bacterial colonization by potentially pathogenic microorganisms occurs in a proportion of patients with Chronic Obstructive Pulmonary Disease (COPD). It increases airway inflammation and influences outcomes negatively. Yet, its diagnosis in clinical practice is not straightforward. The electronic nose is a new non-invasive technology capable of distinguishing volatile organic compound (VOC) breath-prints in exhaled breath. We aim to explore if an electronic nose can reliably discriminate COPD patients with and without airway bacterial colonization.
  
  
  METHODS
  We studied 37 clinically stable COPD patients (67.8 ± 5.2 yrs, FEV1 41 ± 10% ref.) and 13 healthy controls (62.8 ± 5.2 yrs, FEV1 99 ± 10% ref.). The presence of potentially pathogenic microorganisms in the airways of COPD patients (n = 10, 27%) was determined using quantitative bacterial cultures of protected specimen brush. VOCs breath-prints were analyzed by discriminant analysis on principal component reduction, resulting in cross-validated accuracy values. Area Under Receiver Operating Characteristics (AUROC) was calculated using multiple logistic regression.
  
  
  RESULTS
  Demographic, functional and clinical characteristics were similar in colonized and non-colonized COPD patients but their VOC breath-prints were different (accuracy 89%, AUROC 0.92, p > 0.0001). Likewise, VOCs breath-prints from colonized (accuracy 88%, AUROC 0.98, p < 0.0001) and non-colonized COPD patients (accuracy 83%, AUROC 0.93, p < 0.0001) were also different from controls.
  
  
  CONCLUSIONS
  An electronic nose can identify the presence of airway bacterial colonization in clinically stable patients with COPD.
authors.affiliation: Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomédica Sant Pau (IIB Sant Pau), Universitat Autònoma de Barcelona, Department of Medicine, Barcelona Respiratory Network (BRN), Barcelona, Spain. Electronic address: osibila@santpau.cat.
authors.forename: Oriol
authors.initials: O
authors.lastname: Sibila
authors.affiliation: Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomédica Sant Pau (IIB Sant Pau), Universitat Autònoma de Barcelona, Department of Medicine, Barcelona Respiratory Network (BRN), Barcelona, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Garcia-Bellmunt
authors.affiliation: Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomédica Sant Pau (IIB Sant Pau), Universitat Autònoma de Barcelona, Department of Medicine, Barcelona Respiratory Network (BRN), Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Giner
authors.affiliation: RFic Group, École Polytechnique Fédérale de Lausanne, Switzerland.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Merino
authors.affiliation: Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomédica Sant Pau (IIB Sant Pau), Universitat Autònoma de Barcelona, Department of Medicine, Barcelona Respiratory Network (BRN), Barcelona, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Suarez-Cuartin
authors.affiliation: Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomédica Sant Pau (IIB Sant Pau), Universitat Autònoma de Barcelona, Department of Medicine, Barcelona Respiratory Network (BRN), Barcelona, Spain.
authors.forename: Alfons
authors.initials: A
authors.lastname: Torrego
authors.affiliation: Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomédica Sant Pau (IIB Sant Pau), Universitat Autònoma de Barcelona, Department of Medicine, Barcelona Respiratory Network (BRN), Barcelona, Spain.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Solanes
authors.affiliation: Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomédica Sant Pau (IIB Sant Pau), Universitat Autònoma de Barcelona, Department of Medicine, Barcelona Respiratory Network (BRN), Barcelona, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: Castillo
authors.affiliation: Department of Respiratory Medicine, Hospital Son Espases, Palma de Mallorca, CIBER Enfermedades Respiratorias (CIBERES), Spain.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Valera
authors.affiliation: Department of Respiratory Medicine, Hospital Son Espases, Palma de Mallorca, CIBER Enfermedades Respiratorias (CIBERES), Spain.
authors.forename: Borja G
authors.initials: BG
authors.lastname: Cosio
authors.affiliation: Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomédica Sant Pau (IIB Sant Pau), Universitat Autònoma de Barcelona, Department of Medicine, Barcelona Respiratory Network (BRN), Barcelona, Spain.
authors.forename: Vicente
authors.initials: V
authors.lastname: Plaza
authors.affiliation: Thorax Institute, Hospital Clinic, IDIBAPS, Univ Barcelona, FISIB, CIBER Enfermedades Respiratorias (CIBERES), Barcelona Respiratory Network (BRN), Barcelona, Spain.
authors.forename: Alvar
authors.initials: A
authors.lastname: Agusti
mesh_terms: D000368:Aged; D001419:Bacteria / Q000302:isolation & purification*; D001944:Breath Tests / Q000295:instrumentation / Q000379:methods; D016022:Case-Control Studies; D062609:Electronic Nose; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D029424:Pulmonary Disease, Chronic Obstructive / Q000382:microbiology*; D012137:Respiratory System / Q000382:microbiology*; D055549:Volatile Organic Compounds / Q000032:analysis
chemical_list: D055549:Volatile Organic Compounds
keywords: Bacterial colonization; COPD; Inflammation; Volatile organic compounds