title: Quantification and spread of Pneumocystis jirovecii in the surrounding air of patients with Pneumocystis pneumonia.
abstract: BACKGROUND
  Airborne transmission of Pneumocystis has been demonstrated in animal models and is highly probable in humans. However, information concerning burdens of Pneumocystis jirovecii (human-derived Pneumocystis) in exhaled air from infected patients is lacking. Our objective is to evaluate P. jirovecii air diffusion in patients with Pneumocystis pneumonia.
  
  
  METHODS
  Patients admitted with Pneumocystis pneumonia were prospectively enrolled from 9 January 2008 to 21 July 2009. Air samples (1.5 m(3)) were collected on liquid medium with a commercial sampler at 1-, 3-, 5-, and 8-m distances from patients' heads. Air control samples were collected away from Pneumocystis pneumonia patient wards and outdoors. Samples were examined for P. jirovecii detection and quantification using a real-time polymerase chain reaction assay targeting the mitochondrial large subunit ribosomal RNA gene.
  
  
  RESULTS
  Forty patients were diagnosed as having Pneumocystis pneumonia. Air sampling was performed in the environment for 19 of them. At a 1-m distance from patients' heads, P. jirovecii DNA was detected in 15 (79.8%) of 19 patients, with fungal burdens ranging from 7.5 X 10³ to 4.5 X 10⁶ gene copies/m(3). These levels decreased with distance from the patients (P < .002). Nevertheless, 4 (33.3%) of the 12 samples taken at 8 m, in the corridor adjacent to their room, were still positive. Forty control samples were collected and remained negative.
  
  
  CONCLUSIONS
  This study provides the first quantitative data on the spread of P. jirovecii in exhaled air from infected patients. It sustains the risk of P. jirovecii direct transmission in close contact with patients with Pneumocystis pneumonia and leads the way for initiating a quantitative risk assessment for airborne transmission of P. jirovecii.
authors.affiliation: Saint Louis Hospital APHP, Paris-Diderot University, Paris, France.
authors.forename: Firas
authors.initials: F
authors.lastname: Choukri
authors.forename: Jean
authors.initials: J
authors.lastname: Menotti
authors.forename: Claudine
authors.initials: C
authors.lastname: Sarfati
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Lucet
authors.forename: Gilles
authors.initials: G
authors.lastname: Nevez
authors.forename: Yves J F
authors.initials: YJ
authors.lastname: Garin
authors.forename: Francis
authors.initials: F
authors.lastname: Derouin
authors.forename: Anne
authors.initials: A
authors.lastname: Totet
mesh_terms: D000328:Adult; D000368:Aged; D000391:Air Microbiology; D015169:Colony Count, Microbial; D004275:DNA, Ribosomal / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D045363:Pneumocystis carinii / Q000302:isolation & purification*; D011020:Pneumonia, Pneumocystis / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D011446:Prospective Studies; D012331:RNA, Fungal / Q000235:genetics; D012339:RNA, Ribosomal, 28S / Q000235:genetics
chemical_list: D004275:DNA, Ribosomal; D012331:RNA, Fungal; D012339:RNA, Ribosomal, 28S