Efficacy of Selected Respiratory Protective Equipment Challenged with
            <i>Bacillus subtilis</i>
            subsp.
            <i>niger</i>

Johnson, Billy H.; Martin, Daniel D.; Resnick, I G

doi:10.1128/aem.60.6.2184-2186.1994

Cited by 43 publications

(13 citation statements)

References 5 publications

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“…B. atrophaeus (also known as B. subtilis var. niger and B. globigii [BG]) was chosen as the challenge microorganism for this study because it is well-characterized and has been extensively used as a stimulant of biological warfare agents, including B. anthracis (Johnson et al 1994; Franz et al 1997; Hill et al 1999; Helfinstine et al 2005; Luna et al 2008). As a genus-level representative, B. atrophaeus has been utilized to evaluate inactivation techniques such as UV radiation (Shafaat and Ponce 2006), plasma sterilization (Muranyi et al 2007) and thermal sterilization (Kempf et al 2008).…”

Section: Methodsmentioning

confidence: 99%

Association Between Increased DNA Mutational Frequency and Thermal Inactivation of AerosolizedBacillusSpores Exposed to Dry Heat

Johansson

Adhikari

Reponen

et al. 2011

Aerosol Science and Technology

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Inactivation of viable bioaerosol particles, especially stress-resistant microorganisms, has important implications for biodefense and air quality control. It has earlier been shown that the loss of viability of bacterial endospores due to exposure to dry heat is associated with mutational damage. Previous studies, however, used non-aerosolized spores, long exposure times, and moderately elevated temperatures. This study was designed to investigate the mechanism of inactivation of aerosolized Bacillus endospores exposed to high temperatures for sub-second time periods. Bioaerosol was tested in a continuous air flow chamber under two flow rates, 18 L/min and 36 L/min. The chamber had a cylindrical electric heating element installed along its axis. The estimated characteristic exposure temperature (Texposure) ranged from 164°C to 277°C (with an uncertainty of 21–26°C). To quantify mutational frequency, spores were cultivated after dry heat exposure on tryptic-soy agar and on antibiotic nalidixic acid media. Increases in the exposure temperature caused viability loss and increase in mutational frequency of the spore DNA. Significant association was found between the inactivation factor and the mutational frequency ratio (heat exposed versus non-exposed) with R2 of 0.985 for both flow rates combined. The results suggest that mutational damage is involved in the causal chain of events leading to inactivation of aerosolized endospores exposed to heat for sub-second time periods.

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Section: Methodsmentioning

confidence: 99%

Association Between Increased DNA Mutational Frequency and Thermal Inactivation of AerosolizedBacillusSpores Exposed to Dry Heat

Johansson

Adhikari

Reponen

et al. 2011

Aerosol Science and Technology

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“…The PEBS was pilot tested with two microorganisms, gram-positive Bacillus atrophaeus bacterial cells (ATCC 49337, American Type Culture Collection, MD, USA) and fungal spores Penicillium chrysogenum (ATCC 10135), at sampling flow rates Q S D 10 L/min. Both microorganism species have been widely used in bioaerosol studies (Johnson et al 1994;Hill et al 1999;Nadkarni et al 2002). The bacteria were cultured in nutrient broth (Becton, Dickinson and Company, Sparks, MD, USA) for 18 h at 30 C as per our established protocol (Han et al 2015b).…”

Section: Pilot Tests With Biological Particlesmentioning

confidence: 99%

Design and development of a self-contained personal electrostatic bioaerosol sampler (PEBS) with a wire-to-wire charger

Han

Thomas

Mainelis

2017

Aerosol Science and Technology

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Here, we present a concept of a personal electrostatic bioaerosol sampler (PEBS), which is an open channel collector consisting of a novel wire-to-wire particle charger and a collection section housing a double-sided and removable metal collection plate and two quarter-cylinder ground electrodes. The charger consists of a tungsten wire (25.4 mm long and 0.076 mm in diameter) connected to high voltage and positioned in the center of the charging section (a cylinder 50.8 mm long and 25.4 mm in diameter); a ring of stainless steel wire 0.381 mm in diameter surrounds the hot electrode at its midpoint and is grounded. The newly designed wire-to-wire charger produces lower ozone concentrations compared to traditional wire-to-plate or wire-to-cylinder charger designs. The particles captured on the collection plate are easily eluted using water or other fluids. The sampler was iteratively optimized for optimum charging and collection voltages, and collection electrode geometry. When tested with polystyrene latex particles ranging from 0.026 mm to 3.1 mm in diameter and 10 L/min collection flow rate, the sampler's collection efficiency was approximately 70%-80% at charging and collection voltages of C5.5 kV and ¡7 kV, respectively. The PEBS showed this collection efficiency at sampling times ranging from 10 min to 4 h. Preliminary tests with Bacillus atrophaeus bacterial cells and fungal spores of Penicillium chrysogenum showed similar collection efficiency. The use of a unique wire-to-wire charger resulted in ozone production below 10 ppb. Due to low ozone emissions, this sampler will allow maintaining desirable physiological characteristics of the collected bioaerosols, leading to a more accurate sample analysis.

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“…The majority of aerosol penetration occurs at the face seal interface and not through the filter material. (32) All masks need to provide a reasonable leak-tight face seal for optimum protection. For regulation of workplace respiratory protection programs, OSHA gives all FFRs and elastomeric half-mask respirators an assigned protection factor (APF) of 10 regardless of filter type (i.e., N95 or P100).…”

Section: Table II Comparison Of Percent Penetration Measured Using Mmentioning

confidence: 99%

Viable Viral Efficiency of N95 and P100 Respirator Filters at Constant and Cyclic Flow

Gardner

Eshbaugh

Harpest

et al. 2013

Journal of Occupational and Environmental Hygiene

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The growing threat of an influenza pandemic presents a unique challenge to healthcare workers, emergency responders, and the civilian population. The Occupational Safety and Health Administration (OSHA) recommends National Institute for Occupational Safety and Health (NIOSH)-approved respirators to provide protection against infectious airborne viruses in various workplace settings. The filtration efficiency of selected NIOSH-approved particulate N95 and P100 filtering facepiece respirators (FFRs) and filter cartridges was investigated against the viable MS2 virus, a non-pathogenic bacteriophage, aerosolized from a liquid suspension. Tests were performed under two cyclic flow conditions (minute volumes of 85 and 135 L/min) and two constant flow rates (85 and 270 L/min). The mean penetrations of viable MS2 through the N95 and P100 FFRs/cartridges were typically less than 2 and 0.03%, respectively, under all flow conditions. All N95 and P100 FFR and cartridge models assessed in this study, therefore, met or exceeded their respective efficiency ratings of 95 and 99.97% against the viable MS2 test aerosol, even under the very high flow conditions. These NIOSH-approved FFRs and particulate respirators equipped with these cartridges can be anticipated to achieve expected levels of protection (consistent with their assigned protection factor) against airborne viral agents, provided that they are properly selected, fitted, worn, and maintained.

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Efficacy of Selected Respiratory Protective Equipment Challenged with Bacillus subtilis subsp. niger

Cited by 43 publications

References 5 publications

Association Between Increased DNA Mutational Frequency and Thermal Inactivation of AerosolizedBacillusSpores Exposed to Dry Heat

Association Between Increased DNA Mutational Frequency and Thermal Inactivation of AerosolizedBacillusSpores Exposed to Dry Heat

Design and development of a self-contained personal electrostatic bioaerosol sampler (PEBS) with a wire-to-wire charger

Viable Viral Efficiency of N95 and P100 Respirator Filters at Constant and Cyclic Flow

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