Comparison of Methods for Detection and Enumeration of Airborne Microorganisms Collected by Liquid Impingement

Details

• Personal Author:
  Brenner KP ; Donnelly J ; Grinshpun SA ; Stelma GN ; Terzieva S ; Ulevicius V ; Willeke K
• Description:
  Bacterial agents and cell components can be spread as bioaerosols, producing infections and asthmatic problems. This study compares four methods for the detection and enumeration of aerosolized bacteria collected in an AGI-30 impinger. Changes in the total and viable concentrations of Pseudomonas fluorescens in the collection fluid with respect to time of impingement were determined. Two direct microscopic methods (acridine orange and BacLight) and aerodynamic aerosol-size spectrometry (Aerosizer) were employed to measure the total bacterial cell concentrations in the impinger collection fluid and the air, respectively. These data were compared with plate counts on selective (MacConkey agar) and nonselective (Trypticase soy agar) media, and the percentages of culturable cells in the collection fluid and the bacterial injury response to the impingement process were determined'. The bacterial collection rate was found to be relatively unchanged during 60 min of impingement. The aerosol measurements indicated an increased amount of cell fragments upstream of the impinger due to continuous bacterial nebulization. Some of the bacterial clusters, present in the air upstream of the impinger, deagglomerated during impingement, thus increasing the total bacterial count by both direct microscopic methods. The BacLight staining technique was also used to determine the changes in viable bacterial concentration during the impingement process. The percentage of viable bacteria, determined as a ratio of BacLight live to total counts was only 20% after 60 min of sampling. High counts on Trypticase soy agar indicated that most of the injured cells could recover. On the other hand, the counts from the MacConkey agar were very low, indicating that most of the cells were structurally damaged in the impinger. The comparison of data on the percentage of injured bacteria obtained by the traditional plate count with the data on percentage of nonviable bacteria obtained by the BacLight method showed good agreement. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollutants, Occupational Asthma Asthma, Occupational Filtration Microbiology Occupational Health Particulate Matter Safety
• Keywords:
  Aerosol-particles Airborne-particles Author Keywords: Bioaerosols Bacteria Bronchial-asthma Microorganisms Microscopic-analysis Spores
• ISSN:
  0099-2240
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  62
• Issue:
  7
• NIOSHTIC Number:
  nn:20031095
• Citation:
  Appl Environ Microbiol 1996 Jul; 62(7):2264-2272
• Contact Point Address:
  Sergey A. Grinshpun, Aerosol Research Laboratory, Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio 45267-0056
• CAS Registry Number:
  Acridine Orange (CAS RN 65-61-2)
• Federal Fiscal Year:
  1996
• Performing Organization:
  University of Cincinnati, Cincinnati, Ohio
• Peer Reviewed:
  True
• Start Date:
  19950201
• Source Full Name:
  Applied and Environmental Microbiology
• End Date:
  19980731
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:a6ccca21e894bb89ba709674cd7896e4370d35d5db00ca285e0bccd6dc7ba3d61012bfa65af8bf8c8dc99b1b301745743da70999241d25fe392b78d4706f281f
• Download URL:
  https://stacks.cdc.gov/view/cdc/191451/cdc_191451_DS1.pdf
• File Type:
  [PDF - 457.60 KB ]