Article

Cough-generated aerosols of Pseudomonas aeruginosa and other Gram-negative bacteria from patients with cystic fibrosis.

Department of Respiratory Medicine, Royal Children's Hospital and Health Service District, Brisbane, Australia.
Thorax (Impact Factor: 8.38). 08/2009; 64(11):926-31. DOI: 10.1136/thx.2008.112466
Source: PubMed

ABSTRACT Pseudomonas aeruginosa is the most common bacterial pathogen in patients with cystic fibrosis (CF). Current infection control guidelines aim to prevent transmission via contact and respiratory droplet routes and do not consider the possibility of airborne transmission. It was hypothesised that subjects with CF produce viable respirable bacterial aerosols with coughing.
A cross-sectional study was undertaken of 15 children and 13 adults with CF, 26 chronically infected with P aeruginosa. A cough aerosol sampling system enabled fractioning of respiratory particles of different sizes and culture of viable Gram-negative non-fermentative bacteria. Cough aerosols were collected during 5 min of voluntary coughing and during a sputum induction procedure when tolerated. Standardised quantitative culture and genotyping techniques were used.
P aeruginosa was isolated in cough aerosols of 25 subjects (89%), 22 of whom produced sputum samples. P aeruginosa from sputum and paired cough aerosols were indistinguishable by molecular typing. In four cases the same genotype was isolated from ambient room air. Approximately 70% of viable aerosols collected during voluntary coughing were of particles <or=3.3 microm aerodynamic diameter. P aeruginosa, Burkholderia cenocepacia, Stenotrophomonas maltophilia and Achromobacter xylosoxidans were cultivated from respiratory particles in this size range. Positive room air samples were associated with high total counts in cough aerosols (p = 0.003). The magnitude of cough aerosols was associated with higher forced expiratory volume in 1 s (r = 0.45, p = 0.02) and higher quantitative sputum culture results (r = 0.58, p = 0.008).
During coughing, patients with CF produce viable aerosols of P aeruginosa and other Gram-negative bacteria of respirable size range, suggesting the potential for airborne transmission.

0 Bookmarks
 · 
254 Views
  • Source
    08/2014; 35(S1):S1-S67.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Influenza remains a significant threat to public health, yet there is significant uncertainty about the routes of influenza transmission from an infectious source through the environment to a receptor, and their relative risks. Herein, data pertaining to factors that influence the environmental mediation of influenza transmission are critically reviewed, including: frequency, magnitude and size distribution and virus expiration, inactivation rates, environmental and self-contact rates, and viral transfer efficiencies during contacts. Where appropriate, two-stage Monte Carlo uncertainty analysis is used to characterize variability and uncertainty in the reported data. Significant uncertainties are present in most factors, due to: limitations in instrumentation or study realism; lack of documentation of data variability; or lack of study. These analyses, and future experimental work, will improve parameterization of influenza transmission and risk models, facilitating more robust characterization of the magnitude and uncertainty in infection risk.
    Risk Analysis 03/2011; 31(8):1226-42. · 2.28 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Aerosol transmission routes of respiratory viruses have been classified by the WHO on the basis of equilibrium particle size. Droplet transmission is associated with particles sized >5 µm in diameter and airborne transmission is associated with particles sized ≤5 µm in diameter. Current infection control measures for respiratory viruses are directed at preventing droplet transmission, although epidemiological evidence suggests concurrent airborne transmission also occurs. Understanding the size of particles carrying viruses can be used to inform infection control procedures and therefore reduce virus transmission. This study determined the size of particles carrying respiratory viral RNA produced on coughing and breathing by 12 adults and 41 children with symptomatic respiratory infections. A modified six-stage Andersen Sampler collected expelled particles. Each stage was washed to recover samples for viral RNA extraction. Influenza A and B, parainfluenza 1, 2 and 3, respiratory syncytial virus (RSV), human metapneumovirus and human rhinoviruses (hRV) were detected using RT-PCR. On breathing, 58% of participants produced large particles (>5 µm) containing viral RNA and 80% produced small particles (≤5 µm) carrying viral RNA. On coughing, 57% of participants produced large particles containing viral RNA and 82% produced small particles containing viral RNA. Forty five percent of participants produced samples positive for hRV viral RNA and 26% of participants produced samples positive for viral RNA from parainfluenza viruses. This study demonstrates that individuals with symptomatic respiratory viral infections produce both large and small particles carrying viral RNA on coughing and breathing. J. Med. Virol. © 2013 Wiley Periodicals, Inc.
    Journal of Medical Virology 08/2013; · 2.37 Impact Factor

Full-text (3 Sources)

View
50 Downloads
Available from
May 28, 2014