Bioaerosol concentrator performance: comparative tests with viable and with solid and liquid nonviable particles

Kesavan, Jana; Bottiger, Jerold R.; McFarland, Andrew R.

doi:10.1111/j.1365-2672.2007.03560.x

Cited by 15 publications

(28 citation statements)

References 16 publications

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“…The nebulization was completed by with 20 psi air through the nebulizer for 10 minutes. The bioaerosols were used to test different air sampling techniques (Kesavan et al, 2008). Yah and…”

Section: Aerosol Generation Methodsmentioning

confidence: 99%

“…Kesavan et al used a 10 mCi Kr-85 source (TSI, Inc.) to neutralize particles generated through a 24-jet Collison (Kesavan et al, 2008). The system designed by Baron et al had several different methods to neutralize the aerosols.…”

Section: For Vegetativementioning

confidence: 99%

“…Dead organisms can be quantified by PCR or other molecular techniques, but they will clearly not germinate. Because of this, sensitivity and repeatability may not be particularly good when using culture methods (Kesavan, 2008). Additionally, dehydration effects can kill sensitive bacteria.…”

mentioning

confidence: 99%

“…Some of the Bacillus subtilis species were actually renamed a new strain, Bacillus atrophaeus subsp globigii (Burke et al, 2004). Again, there are several tests and studies which have used Bacillus atropheaus (Brown et al, 2008a;Carrera et al, 2005;Kesavan, 2008;Lewandowski et al, 2010;Martin and Moore, 2001;Thomas et al, 2008;). …”

mentioning

confidence: 99%

“…The size of the chamber required that a 24-jet Collison nebulizer be used followed by a 10 milliCurie Kr-85 source used for neutralization. Initial tests used inert particles; however, research has shown that biological particle tests are ultimately required (Kesavan, 2008).…”

mentioning

confidence: 99%

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Decontamination of Bioaerosols within Engineering Tolerances of Aircraft Materials

Frazey¹,

Reynolds²

2012

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DECONTAMINATION OF BIOAEROSOLS WITHIN ENGINEERING TOLERANCES OF AIRCRAFT MATERIALSBacillus anthracis spores are generally considered the most difficult biological agents to decontaminate or inactivate. Inactivation of these spores is further complicated on aircraft because engineering specifications do not allow for chemical disinfectants to be used. Aircraft, however, must meet strict engineering specifications, requiring extended storage at temperatures greater than 185° F at 100% relative humidity (RH). Heat and humidity near these levels have been tested to determine if they can inactivate spores; however, these studies have only evaluated spores in high concentrations (10 6 spores) on aluminum coupons. This dissertation research was designed to evaluate the effectiveness of high heat and humidity on Bacillus atrophaeus subsp globigii (BG) spores, a simulant commonly used for Bacillus anthracis, when delivered via three different methods onto two different materials.In Chapter 2, an innovative bioaerosol deposition chamber design and testing is described. The test chamber was designed to deposit Bacillus atrophaeus subsp globigii (BG) spores onto coupons modeling real aircraft components. Deposition equations were derived to model the spore deposition. Initial deposition tests with fluorescent particles were inconclusive because the limit of quantification could not be reached; therefore, the BG spores were used to test deposition. Initial tests demonstrated the parameters that could be manipulated throughout the experiments to control the spore deposition. After these were evaluated, four final tests were completed to perform more in-depth statistical analysis. The coefficients of variation for these tests were within acceptable ranges (all were 25.5% or less). Ryan-Joiner tests were performed iii on the data and showed that 2 of the 4 tests displayed a lognormal distribution, while the other 2 tests were inconclusive. All data was therefore treated as a lognormal distribution. Contour plots were then constructed to determine if a discernible pattern was present. While these contour plots showed a somewhat even dispersion, there were no discernible patterns.Additionally, the plots showed a wide range of spore deposition throughout the four tests.Finally, the equations derived for spore deposition were validated. The data showed that 8.67%up to 31.0% (average of 20.25%) of the spores modeled could actually deposit and be recovered through culture methods. These losses could have occurred during the nebulization through inactivation or clumping after the spores were aerosolized. Regardless, this showed that the equations could be used after accounting for these losses. The study demonstrated that the test chamber can be used for spore depositions with the caveat that future studies include an appropriate control coupon next to each sample.In Chapter 3, decontamination of aluminum coupons was evaluated using the BG spores inoculated in three different methods-high direct inoculation (10 6 spores per c...

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“…The nebulization was completed by with 20 psi air through the nebulizer for 10 minutes. The bioaerosols were used to test different air sampling techniques (Kesavan et al, 2008). Yah and…”

Section: Aerosol Generation Methodsmentioning

confidence: 99%

Section: For Vegetativementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Decontamination of Bioaerosols within Engineering Tolerances of Aircraft Materials

Frazey¹,

Reynolds²

2012

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Estimation of Viable Spores in Bacillus atrophaeus (BG) Particles of 1 to 9 μm Size Range

Duncan¹,

Ho²

2008

CLEAN Soil Air Water

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This study examined the viable organism content in a bioaerosol disseminated from a letter contaminated with Bacillus atrophaeus (BG) (anthrax simulant). In addition to using nutrient medium based slit samplers to sample the bioaerosol in the air space where the dispersion occurred, the individual who opened the contaminated letter was also used as a bioaerosol sampler by incorporating an external filter trap positioned over the inlet of the respirator filter canister worn by the individual. The reasons for this latter approach should be clear: it would provide actual quantitative information on the inhalation exposure hazard to an individual faced with this scenario. Where bioaerosol particles may be comprised of aggregates of many smaller particles, organism viability within the aggregate is important and may have an impact on the current definition of ‘infectious dose’ or ‘lethal dose’. Both terms assume single organism counts. Results from two different methods of measuring aerosols due to opening contaminated letters are presented: slit samplers and glass microfibre filter medium placed on the inlet port of a respirator cartridge. The total number of viable bioaerosol particles measured at the inhalation port of the filter canister was 40 times greater than measured by the slit samplers. Accordingly, this may be accounted for by a distribution of bioaerosol particles comprised of aggregates of single BG spores. A model has been proposed that estimates the number of individual viable spores in a distribution of aerosol particles through a relatively simple probability density function distribution for particle size, and which incorporates realistic assumptions regarding particle diameters, packing density and spore viability.

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Evaluation criteria for bioaerosol samplers

Kesavan

Sagripanti

2015

Environ. Sci.: Processes Impacts

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Humans contract a variety of serious diseases through inhalation of infectious aerosols. Thus, the importance of monitoring air for microbial, toxic, or allergic content is recognized in clinical, occupational, and biodefense arenas. However, accurate monitoring of potentially contaminated environments can be hampered by selection of aerosol samplers with inadequate performance for the intended task. In this study, 29 aerosol samplers were evaluated based on their respective air flow, size, weight, power consumption, and efficiency in sampling particles in the respirable range. The resulting data demonstrates that sampling air flow and efficiency vary widely, and cannot be predicted from the physical characteristics of air samplers, and hence, that proper selection of air samplers should be more involved than shopping for a device based on the limited characteristics that are published by the manufacturers. The findings are summarized in an approach to rationally select bioaerosol samplers for use in infection control and environmental biomonitoring. The presented data demonstrates that inadequate selection of air samplers could result in a failure to collect particles of interest and thus, underestimate the risk and provide a false sense of security in contaminated health care settings and environments contaminated with infectious or toxic aerosols.

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Bioaerosol concentrator performance: comparative tests with viable and with solid and liquid nonviable particles

Cited by 15 publications

References 16 publications

Decontamination of Bioaerosols within Engineering Tolerances of Aircraft Materials

Decontamination of Bioaerosols within Engineering Tolerances of Aircraft Materials

Estimation of Viable Spores in Bacillus atrophaeus (BG) Particles of 1 to 9 μm Size Range

Evaluation criteria for bioaerosol samplers

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