Contamination of Aerosol with Pseudomonas Aeruginosa Introduced via Mouthpiece in Different Nebulizer Designs

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Patricia A Dailey James B Fink


Background: Nebulizers have been associated with bacterial and viral contamination likely from drooling or expulson of oral secretions into the nebulizer mouthpiece.  We hypothesized that simulated “drooling” could result in contamination of the nebulizer medication resulting in aerosolization of potential pathogens.

Method: We evaluated four nebulizers: Continuous jet nebulizer (CJN: MistyMax, Allegiance, USA), breath enhanced  (BEN:LC Sprint; Pari, Germany), breath actuated (BAN; AeroEclipse Monaghan/Trudell, Canada) and vibrating mesh nebulizer  (VMN; Aerogen with Ultra, Aerogen Ltd, Galway, Ireland) operated per manufacturer recommendations with 3 mL of NSS.  Pseudomonas aeruginosa broth (2 mL) was pipetted into the mouthpiece of each nebulizer in an upright postion simulating a patient drooling into the device. Aerosol was produced for 30-60 seconds and collected on Triptic Soy Agar (TSA) plate, prior, immeadiately, and 4-5 hours post instillation. Colony counts were done post incubation (3-5 days).

Results: P. aeruginosa colony counts prior, immediately, and four hours after instillation; BAN (0, 110, and 122 CFU/m); and BEN (0, Too Numerous To Count (TNC), and TNC), VMN: (0, 0, and 0 CFU/mL) and  CJN (0, 0, and 0 CFU/mL), respectively.

Conclusions:  Nebulizer  type and design influence impact of pathogen containing fluids passing through the mouthpiece contaminating the aerosol generated. 

Keywords: nebulizer, contamination, infection prevention, aerosol, jet nebulizer, vibrating mesh nebulizer

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How to Cite
DAILEY, Patricia A; FINK, James B. Contamination of Aerosol with Pseudomonas Aeruginosa Introduced via Mouthpiece in Different Nebulizer Designs. Medical Research Archives, [S.l.], v. 10, n. 6, june 2022. ISSN 2375-1924. Available at: <>. Date accessed: 20 apr. 2024. doi:
Research Articles


1. Tran K, Simon K, Severn M, Pessoa-Silva CL, Conly J. Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: A systematic review. PloS One. 2012;7(4):e35797.
2. Siegel JD, Rhinehart E, Jackson M, Chiarello L. 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Health Care Settings. Am J of Infect Control. 2007;35(10 Suppl2):S65-S164. Doi:10.1016/i.ajic.2007.10.007
3. WHO. Clinical management of severe acute respiratory infection when novel coronavirus (nCoV) infection is suspected. World Health Organization. Published 2020. Accessed May 6, 2022.
4. Srikanth P, Sudharsanam S, Steinberg R, Bio-aerosols in indoor environment: composition, health effects and analysis. Infiain J Med Microbiol.2008;26(4):302-312. Doi:10.4103/0255-857.4355
5. Craven, D. E., Lichtenberg, D. A., Goularte, T. A., Make, B. J., & McCabe, W. R. (1984). Contaminated medication nebulizers in mechanical ventilator circuits. Source of bacterial aerosols. Am J Med. 1984 77(5):834-838. Doi:10.1016/0002-9343(84)90520-5
6. Fink JB, Ehrmann S, Li J, et al. Reducing Aerosol-Related Risk of Transmission in the Era of COVID-19: An Interim Guidance Endorsed by the International Society of Aerosols in Medicine. J Aerosol Med Pulm Drug Deliv. 2020;33(6):300-304. doi:10.1089/jamp.2020.1615
7. O’Malley CA. Device cleaning and infection control in aerosol therapy [published correction appears in Respir Care. 2015 Aug;60(8):e150]. Respir Care 2015;60(6):917-930.
8. CDC. Guidelines for prevention of nosocomial pneumonia. Centers for Disease Control and Prevention. MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports. Published 2003. Accessed May 6, 2022.
9. Dubosky MN, Chen Y-FF, Henriksen ME, Vines DL. Vibrating Mesh Nebulizer Compared With Metered-Dose Inhaler in Mechanically Ventilated Subjects. Respir Care. 2017; 62(4): 391-395. Doi:10.4187/respcare.04823
10. Branson RD, Hess DR, Kallet R, Robinson L. SARS COV-2 - AARC. AARC. Published 2020. Accessed May 6, 2022.
11. Gilmore TW. Use of a metered-dose inhaler compared with a vibrating mesh nebulizer during mechanical ventilation: Does it really matter? Respir. Care. 2017;62(4):513-514. doi:10.4187/respcare.05464
12. Dubosky MN, Lamorena E, Jones C, et al. B24. critical care: Acute respiratory failure - mechanical ventilation and beyond. American Thoracic Society International Conference Meetings Abstracts American Thoracic Society International Conference Meetings Abstracts. Published 2017. Accessed May 6, 2022.
13. Goldstein KM, Ghadimi K, Mystakelis H, et al. Risk of Transmitting Coronavirus Disease 2019 During Nebulizer Treatment: A Systematic Review. J Aerosol Med Pulm Drug Deliv. 2021;34(3):155-170. Doi:10.1089/jamp.2020.1659
14. Halpin DMG, Criner GJ, Papi A, et al. Global Initiative for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease. The 2020 GOLD Science Committee Report on COVID-19 and Chronic Obstructive Pulmonary Disease. Am J Respir Crit Care Med. 2021;203(1):24-36. doi:10.1164/rccm.202009-3533SO