Method to Determine the Number of Bacterial Spores Within Aerosol Particles

Carrera, Mónica; Kesavan, Jana; Zandomeni, Rubén; Sagripanti, José-Luis

doi:10.1080/02786820500352098

Cited by 30 publications

(25 citation statements)

References 12 publications

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“…This finding agrees with previous observations on the composition of aerosolized B. atrophaeus spores (Carrera et al 2005). Since bacteria in particles of different size could be differentially protected from UV inactivation, the data in Figure 4 indicates that all bacteria should be similarly exposed to UV without substantial protection by shielding inside clumps or large particles.…”

Section: Characterization Of Aerosol Exposuresupporting

confidence: 82%

Germicidal UV Sensitivity of Bacteria in Aerosols and on Contaminated Surfaces

King

Kesavan

Sagripanti

2011

Aerosol Science and Technology

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We compared the UV sensitivity of Bacillus atrophaeus (a surrogate for B. anthracis), Pantoea agglomerans (a bacterial simulant frequently used in biodefense studies), and Yersinia ruckeri (a surrogate for Yersinia pestis) either airborne or deposited on a semisolid (wet) agar surface. Bacterial vegetative cells were aerosolized into an exposure chamber and exposed for various lengths of time to an ultraviolet (UV) light source emitting at 254 nanometer (nm) (in the UVC region also known as UVGI). Aerosols were collected onto gelatin filters, which were dissolved, diluted, plated, and incubated to enumerate colony formation. In darkness (with the UV light

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Section: Characterization Of Aerosol Exposuresupporting

confidence: 82%

Germicidal UV Sensitivity of Bacteria in Aerosols and on Contaminated Surfaces

King

Kesavan

Sagripanti

2011

Aerosol Science and Technology

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“…This phenomenon is proposed to be due to larger particles containing higher numbers of bacteria in aggregates, enabling a fraction to survive deleterious stresses encountered during aerosolization. The outer layer of bacteria effectively is sacrificial, enabling the bacteria within the core of the aggregate to survive (4,28); such aggregation of B. atrophaeus spores was observed in this study (Fig. 3).…”

Section: Discussionmentioning

confidence: 67%

Characterization and Deposition of Respirable Large- and Small-Particle Bioaerosols

Thomas

Webber

Sellors

et al. 2008

Appl Environ Microbiol

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The deposition patterns of large-particle microbiological aerosols within the respiratory tract are not well characterized. A novel system (the flow-focusing aerosol generator [FFAG]) which enables the generation of large (>10-m) aerosol particles containing microorganisms under laboratory conditions was characterized to permit determination of deposition profiles within the murine respiratory tract. Unlike other systems for generating large aerosol particles, the FFAG is compatible with microbiological containment and the inhalational challenge of animals. By use of entrapped Escherichia coli cells, Bacillus atrophaeus spores, or FluoSphere beads, the properties of aerosols generated by the FFAG were compared with the properties of aerosols generated using the commonly available Collison nebulizer, which preferentially generates small (1-to 3-m) aerosol particles. More entrapped particulates (15.9-to 19.2-fold) were incorporated into 9-to 17-m particles generated by the FFAG than by the Collison nebulizer. The 1-to 3-m particles generated by the Collison nebulizer were more likely to contain a particulate than those generated by the FFAG. E. coli cells aerosolized using the FFAG survived better than those aerosolized using the Collison nebulizer. Aerosols generated by the Collison nebulizer and the FFAG preferentially deposited in the lungs and nasal passages of the murine respiratory tract, respectively. However, significant deposition of material also occurred in the gastrointestinal tract after inhalation of both the small (89.7%)-and large (61.5%)-particle aerosols. The aerosols generated by the Collison nebulizer and the FFAG differ with respect to mass distribution, distribution of the entrapped particulates, bacterial survival, and deposition within the murine respiratory tract.Environmental bioaerosols can have a profound influence on human health, due to infectious disease, hypersensitivity conditions (e.g., hay fever), and acute inflammatory responses resulting from the inhalation of irritants. Environmental aerosols comprise a polydisperse distribution composed of a range of particle sizes from submicron to large droplets thousands of microns in diameter. Hence, such aerosols contain a proportion of particles of Ͼ10 m, herein defined as "large particles." Indeed, analysis of the particle sizes containing bacteria within the atmosphere indicated that ϳ40% are greater than 7 m, due to adherence to debris (27). Environmental microbial aerosols can arise from a number of sources, including food processing (13,19,40); water sources, e.g., contaminated air conditioning systems, shower heads, water faucets, and cooling towers (2, 42, 53); pesticide sprayers (1); and fungal-spore generation (15, 26). The importance of bioaerosols from a civilian biodefense perspective was highlighted by the U.S. anthrax mail attacks in 2001 (3).In health care settings, nosocomial transmission may occur by patients coughing or sneezing, generating respirable particles within the diameter range of 0.5 to 12 m (6, 14); alternat...

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“…Carrera et al demonstrated that the output of the MDIs (0.05% [wt/wt]) used in this study could be particles containing single spores or particles containing multiple spores (7). In the first set of measurements, they used optical microscopy to determine particle area.…”

Section: Discussionmentioning

confidence: 99%

Development of an Aerosol Surface Inoculation Method for Bacillus Spores

Ryan

Snyder

2011

Appl Environ Microbiol

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A method was developed to deposit Bacillus subtilis spores via aerosolization onto various surface materials for biological agent decontamination and detection studies. This new method uses an apparatus coupled with a metered dose inhaler to reproducibly deposit spores onto various surfaces. A metered dose inhaler was loaded with Bacillus subtilis spores, a surrogate for Bacillus anthracis. Five different material surfaces (aluminum, galvanized steel, wood, carpet, and painted wallboard paper) were tested using this spore deposition method. This aerosolization method deposited spores at a concentration of more than 10 7 CFU per coupon (18-mm diameter) with less than a 50% coefficient of variation, showing that the aerosolization method developed in this study can deposit reproducible numbers of spores onto various surface coupons. Scanning electron microscopy was used to probe the spore deposition patterns on test coupons. The deposition patterns observed following aerosol impaction were compared to those of liquid inoculation. A physical difference in the spore deposition patterns was observed to result from the two different methods. The spore deposition method developed in this study will help prepare spore coupons via aerosolization fast and reproducibly for bench top decontamination and detection studies.In response to the 2001 Bacillus anthracis spore incidents in the United States, many studies have investigated various technologies to sample media, detect biological agents, and decontaminate materials (3,9,10,(17)(18)(19)21). These laboratory studies typically use small coupons and laboratory inoculants to simulate the materials and biological agents that occur in field events. In these studies, test coupons should have reproducible numbers of viable spores on varied surface types. In addition, it is critical that the coupons are prepared so that the inoculation is representative of contamination as it occurs in the field. Liquid inoculation protocols that use suspended spores in aqueous buffers have been the primary methods used to prepare test surfaces for biological agent decontamination and detection studies (15,16,20). Liquid inoculation methods offer advantages in that they allow relatively easy control of the number of spores and the contaminated area. However, it is unclear whether surfaces contaminated by liquid inoculation methods are representative of surfaces contaminated with aerosolized Bacillus anthracis spores. Therefore, it is necessary to investigate the impact of various spore deposition methods on Bacillus anthracis decontamination and detection studies.The conventional particle deposition method via aerosolization is comprised of an aerosol generating system, such as a particle nebulizer, to introduce the spores into a chamber and a second chamber to allow the spores to settle onto the target material surfaces. The spore surface concentrations are controlled by varying settling time and the initial aerosolized spore concentration in the chamber. tested various methods of collecting ...

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Method to Determine the Number of Bacterial Spores Within Aerosol Particles

Cited by 30 publications

References 12 publications

Germicidal UV Sensitivity of Bacteria in Aerosols and on Contaminated Surfaces

Germicidal UV Sensitivity of Bacteria in Aerosols and on Contaminated Surfaces

Characterization and Deposition of Respirable Large- and Small-Particle Bioaerosols

Development of an Aerosol Surface Inoculation Method for Bacillus Spores

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