Face Masks and Cough Etiquette Reduce the Cough Aerosol Concentration of Pseudomonas aeruginosa in People with Cystic Fibrosis

Michelle E Wood, Rebecca E Stockwell, Graham R Johnson, Kay A Ramsay, Laura J Sherrard, Nassib Jabbour, Emma Ballard, Peter O'Rourke, Timothy J Kidd, Claire E Wainwright, Luke D Knibbs, Peter D Sly, Lidia Morawska, Scott C Bell

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RATIONALE: People with cystic fibrosis (CF) generate Pseudomonas aeruginosa in droplet nuclei during coughing. The use of surgical masks has been recommended in healthcare settings to minimise pathogen transmission between CF patients.

OBJECTIVE: To determine if face masks and cough etiquette reduce viable P. aeruginosa aerosolised during cough.

METHODS: Twenty-five adults with CF and chronic P. aeruginosa infection were recruited. Participants performed six talking and coughing maneuvers, with or without face masks (surgical and N95) and hand covering the mouth when coughing (cough etiquette) in an aerosol-sampling device. An Andersen Impactor sampled the aerosol at 2-meters from each participant. Quantitative sputum and aerosol bacterial cultures were performed and participants rated the mask comfort levels during the cough maneuvers.

MEASUREMENTS AND MAIN RESULTS: During uncovered coughing (reference maneuver), 19/25 (76%) participants produced aerosols containing P. aeruginosa, with a positive correlation found between sputum P. aeruginosa concentration (CFU/mL) and aerosol P. aeruginosa CFUs. There was a reduction in aerosol P. aeruginosa load during coughing with surgical mask, coughing with N95 mask and cough etiquette compared with uncovered coughing (p<0.001). A similar reduction in total CFUs was observed for both masks during coughing, yet participants rated surgical masks more comfortable (p=0.013). Cough etiquette provided approximately half the reduction of viable aerosols of the mask interventions during voluntary cough. Talking was a low viable aerosol producing activity.

CONCLUSIONS: Face masks reduce cough generated P. aeruginosa aerosols, with the surgical mask providing enhanced comfort. Cough etiquette was less effective at reducing viable aerosols.

Original languageEnglish
Pages (from-to)1-34
JournalAmerican Journal of Respiratory and Critical Care Medicine
Issue number3
Early online date20 Sep 2017
Publication statusEarly online date - 20 Sep 2017


  • Journal Article

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