PT  - JOURNAL ARTICLE
AU  - Luke D Knibbs
AU  - Graham R Johnson
AU  - Timothy J Kidd
AU  - Joyce Cheney
AU  - Keith Grimwood
AU  - Jacqueline A Kattenbelt
AU  - Peter K O'Rourke
AU  - Kay A Ramsay
AU  - Peter D Sly
AU  - Claire E Wainwright
AU  - Michelle E Wood
AU  - Lidia Morawska
AU  - Scott C Bell
TI  - Viability of <em>Pseudomonas aeruginosa</em> in cough aerosols generated by persons with cystic fibrosis
AID  - 10.1136/thoraxjnl-2014-205213
DP  - 2014 Aug 01
TA  - Thorax
PG  - 740--745
VI  - 69
IP  - 8
4099  - http://thorax.bmj.com/content/69/8/740.short
4100  - http://thorax.bmj.com/content/69/8/740.full
SO  - Thorax2014 Aug 01; 69
AB  - Background Person-to-person transmission of respiratory pathogens, including Pseudomonas aeruginosa, is a challenge facing many cystic fibrosis (CF) centres. Viable P aeruginosa are contained in aerosols produced during coughing, raising the possibility of airborne transmission. Methods Using purpose-built equipment, we measured viable P aeruginosa in cough aerosols at 1, 2 and 4 m from the subject (distance) and after allowing aerosols to age for 5, 15 and 45 min in a slowly rotating drum to minimise gravitational settling and inertial impaction (duration). Aerosol particles were captured and sized employing an Anderson Impactor and cultured using conventional microbiology. Sputum was also cultured and lung function and respiratory muscle strength measured. Results Nineteen patients with CF, mean age 25.8 (SD 9.2) years, chronically infected with P aeruginosa, and 10 healthy controls, 26.5 (8.7) years, participated. Viable P aeruginosa were detected in cough aerosols from all patients with CF, but not from controls; travelling 4 m in 17/18 (94%) and persisting for 45 min in 14/18 (78%) of the CF group. Marked inter-subject heterogeneity of P aeruginosa aerosol colony counts was seen and correlated strongly (r=0.73–0.90) with sputum bacterial loads. Modelling decay of viable P aeruginosa in a clinic room suggested that at the recommended ventilation rate of two air changes per hour almost 50 min were required for 90% to be removed after an infected patient left the room. Conclusions Viable P aeruginosa in cough aerosols travel further and last longer than recognised previously, providing additional evidence of airborne transmission between patients with CF.