The Cough Cylinder: a tool to study measures against airborne spread of (myco-) bacteria.

Abstract

BACKGROUND: 'Covering your cough' reduces droplet number, but its effect on airborne pathogen transmission is less clear. The World Health Organization specifically recommends cough etiquette to prevent the spread of Mycobacterium tuberculosis, but implementation is generally poor and evidence supporting its value is lacking. METHODS: We constructed a model to assess 'real life' transmission risk by counting viable pathogens from aerosols produced by coughing patients, thus allowing the assessment of outward protection measures in a standardised fashion. During the validation process, we focused on rod-shaped bacteria as surrogates for M. tuberculosis. RESULTS: The Cough Cylinder enabled us to sample Pseudomonas aeruginosa, Escherichia coli and mycobacteria from aerosols produced by patients with cystic fibrosis, primary ciliary dyskinesia and tuberculosis. Pathogens in droplets and in airborne particles could be sampled. Delayed air sampling allowed specific measurement of persistent airborne particles. CONCLUSION: This novel experimental system allows measurement of aerosol pathogen spread in a highly standardised fashion. It also offers the possibility to assess the impact of different interventions to limit aerosol transmission.