Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

Comparison of methods for detection and enumeration of airborne microorganisms collected by liquid impingement.

Authors
Terzieva-S; Donnelly-J; Ulevicius-V; Grinshpun-SA; Willeke-K; Stelma-GN; Brenner-KP
Source
Appl Environ Microbiol 1996 Jul; 62(7):2264-2272
NIOSHTIC No.
20031095
Abstract
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.
Keywords
Microbiology; Airborne-particles; Microorganisms; Bacteria; Bronchial-asthma; Aerosols; Aerosol-particles; Microscopic-analysis; Author Keywords: Bioaerosols; Filtration; Microorganisms; Spores
CODEN
AEMIDF
CAS No.
65-61-2
Publication Date
19960701
Document Type
Journal Article
Funding Amount
746102
Funding Type
Grant
Fiscal Year
1996
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-003244
Issue of Publication
7
ISSN
0099-2240
Source Name
Applied and Environmental Microbiology
State
OH
Performing Organization
University of Cincinnati, Cincinnati, Ohio
TOP