(More) viable cough aerosols from individuals with cystic fibrosis

Abstract

Objectives: Cough-generated airborne P. aeruginosa droplet nuclei can remain viable for up 45 minutes. This prompted changes to infection control guidelines for patients with cystic fibrosis (CF). This study investigated if other CF respiratory pathogens are detectable in cough aerosols and assessed their survival over distance and time. Methods: 27 subjects with CF, mean age 28.6 years (SD 9.7); mean FEV1 63.1% (26.2) predicted were enrolled into 2 groups: 1. non-P. aeruginosa Gram-negative bacteria (GNB), 2. Gram-positive bacteria (GP), Staphylococcus aureus. Subjects performed a series of voluntary coughing into 2 validated aerosol-sampling devices to measure viability at 2 and 4m and after 5, 15 and 45 min following generation. An Anderson Impactor collected and sized the aerosols, and total CFU (stages 1-6) was measured. Quantitative sputum and cough aerosol cultures were performed. Results: 11/16 (69%) subjects with mean sputum GNB concentration of 1.9×108 CFU/mL (8.0×103-2.2×109) produced viable aerosol containing the target pathogen. The mean (range) CFU identified in cough aerosol at 4m and at 45 min was 21.6 (0-164) and 15.6 (0-123), respectively. 10/17 (59%) subjects with mean GP sputum concentration of 2.0×107 CFU/mL (1.0×103-1.0×108) produced viable cough aerosol containing S. aureus. A mean (range) of 7.1 CFU (0-55) and 1.0 CFU (0-7) were detected at 4m and at 45 min, respectively. Conclusion: CF respiratory pathogens, other than P. aeruginosa, are viable at 4 metres and for up to 45 minutes after coughing, which highlights the need for universal and stringent infection control.L6143236992017-02-10 <br />