A study of bacterial culturability during bioaerosol challenge test using a test chamber

Hasegawa, Norio; Yamasaki, S.; Horiguchi, Y.

doi:10.1016/j.jaerosci.2011.02.009

Cited by 13 publications

(7 citation statements)

References 34 publications

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“…Landman et al (2004) have observed the limit of detection of Enteroccocus faecalis equal to 7.94 × 10 3 CFU/m 3 of air collected using the Sartorius MD8 sampler when bacteria were aerosolized in an empty isolator (with a volume of 1.3 m 3 ). In a study performed by Hagesawa et al (2011), the mean number of Staphylococcus epidermidis cells collected using the Sartorius MD8 sampler and estimated with the pour plate method was above 10 4 CFU/m 3 , when the concentration of aerosolized bacteria was 1.3 × 10 5 CFU/m 3 . Unfortunately, in these studies, B. atrophaeus endospores were not used, and the bacteria were aerosolized in the experimental chambers filled with the HEPA-filtered air only.…”

Section: Discussionmentioning

confidence: 98%

Evaluation of applicability of the Sartorius Airport MD8 sampler for detection of Bacillus endospores in indoor air

Lewandowski

Kozłowska

Szpakowska

et al. 2012

Environ Monit Assess

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This study was designed to evaluate the measuring range and lowest limit of detection of Bacillus endospores in the ambient room air when the Sartorius MD8 sampler, and two different culture methods for bacterial enumeration were used. Different concentrations of bioaerosol were generated inside the test chamber filled with either the high-efficiency particulate air (HEPA)-filtered air or with the ambient room air. The detection of endospores in the HEPA-filtered air was achievable: (1) when they were aerosolized at a concentration above 7.56 × 103 CFU/m3 and analyzed with spread plate method, and (2) when they were aerosolized at a concentration above 4.00 × 102 CFU/m3 and analyzed with pour plate method. The detection of endospores in the ambient room air was possible: (1) when they were aerosolized at a concentration above 9.1 × 103 CFU/m3 and analyzed with spread plate method, and (2) when they were aerosolized at a concentration above 5.6 × 102 CFU/m3 and analyzed with pour plate method. The microorganisms present in the ambient room air interfere with precise quantification of Bacillus endospores when their concentration is relatively low. The results of this study may be helpful in critical assessment of the results obtained from monitoring the air for bacterial endospores.

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Section: Discussionmentioning

confidence: 98%

Evaluation of applicability of the Sartorius Airport MD8 sampler for detection of Bacillus endospores in indoor air

Lewandowski

Kozłowska

Szpakowska

et al. 2012

Environ Monit Assess

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“…Although the aerobiological stability characteristics of several species of Gramnegative bacteria already have been investigated, including S. marcescens (7,8,17,18), E. coli (19)(20)(21)(22)(23)(24)(25), and P. agglomerans (6,12,(26)(27)(28)(29)(30), most of these studies were performed more than 3 decades ago; thus, several knowledge gaps still remain. An inherent challenge regarding the aerobiological stability of Gram-negative bacteria is the observation that few generalizations seem to be applicable, suggesting that different genera, species, and even strains of Gram-negative bacteria have to be considered separate entities regarding their stability characteristics (11,15,16).…”

Section: Single-cell Particles and Cell Clusters Produced From Differmentioning

confidence: 99%

Aerobiological Stabilities of Different Species of Gram-Negative Bacteria, Including Well-Known Biothreat Simulants, in Single-Cell Particles and Cell Clusters of Different Compositions

Dybwad

Skogan

2017

Appl Environ Microbiol

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The ability to perform controlled experiments with bioaerosols is a fundamental enabler of many bioaerosol research disciplines. A practical alternative to using hazardous biothreat agents, e.g., for detection equipment development and testing, involves using appropriate model organisms (simulants). Several species of Gram-negative bacteria have been used or proposed as biothreat simulants. However, the appropriateness of different bacterial genera, species, and strains as simulants is still debated. Here, we report aerobiological stability characteristics of four species of Gram-negative bacteria (Pantoea agglomerans, Serratia marcescens, Escherichia coli, and Xanthomonas arboricola) in single-cell particles and cell clusters produced using four spray liquids (H 2 O, phosphate-buffered saline [PBS], spent culture medium [SCM], and a SCM-PBS mixture). E. coli showed higher stability in cell clusters from all spray liquids than the other species, but it showed similar or lower stability in single-cell particles. The overall stability was higher in cell clusters than in single-cell particles. The highest overall stability was observed for bioaerosols produced using SCM-containing spray liquids. A key finding was the observation that stability differences caused by particle size or compositional changes frequently followed species-specific patterns. The results highlight how even moderate changes to one experimental parameter, e.g., bacterial species, spray liquid, or particle size, can strongly affect the aerobiological stability of Gram-negative bacteria. Taken together, the results highlight the importance of careful and informed selection of Gram-negative bacterial biothreat simulants and also the accompanying particle size and composition. The outcome of this work contributes to improved selection of simulants, spray liquids, and particle size for use in bioaerosol research.IMPORTANCE The outcome of this work contributes to improved selection of simulants, spray liquids, and particle size for use in bioaerosol research. Taken together, the results highlight the importance of careful and informed selection of Gramnegative bacterial biothreat simulants and also the accompanying particle size and composition. The results highlight how even moderate changes to one experimental parameter, e.g., bacterial species, spray liquid, or particle size, can strongly affect the aerobiological stability of Gram-negative bacteria. A key finding was the observation that stability differences caused by particle size or compositional changes frequently followed species-specific patterns.

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“…A nebulizer was placed in the 10 cm below the top of the chamber and a tube to supply nitrogen gas was connected for nebulization. Nebulizing was performed at the flow rate of about 9 l/min by controlling the valves, and for this flow rate, the air pressure was approximately 2.5 bars . This type of nebulizer produces particles in the range of 1–5 µm, which is favourable for the generation of aerosolized bacteria.…”

Section: Methodsmentioning

confidence: 99%

Assessing of Flexible Packaging Integrity: Using the Aerosolization Bacteria

2016

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Package integrity is a critical factor to ensure that product sterility is maintained over its entire shelf life. An exposure chamber method was developed to determine the integrity of flexible packaging systems, i.e. flexible multilayer linear low‐density polyethylene/nylon pouches with a 100, 50, 25 or 15 µm micro‐channel with 5 mm length defect in the sealing area. Viable cells of Staphylococcus aureus and Escherichia coli have been utilized as model organisms. The aerosol was generated by a nebulizer, about 2.0 × 107 CFU m−3 concentration inside the test chamber. The results demonstrated that defect pouches with a 100, 50 or 25 µm channel leakage exposed to microbiologically challenging conditions could not maintain the sterility of their contents. Micro‐channels with 15 µm diameter can be detected as the critical micro‐channel dimension for bacterial penetration for flexible pouches. Copyright © 2016 John Wiley & Sons, Ltd.

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A study of bacterial culturability during bioaerosol challenge test using a test chamber

Cited by 13 publications

References 34 publications

Evaluation of applicability of the Sartorius Airport MD8 sampler for detection of Bacillus endospores in indoor air

Evaluation of applicability of the Sartorius Airport MD8 sampler for detection of Bacillus endospores in indoor air

Aerobiological Stabilities of Different Species of Gram-Negative Bacteria, Including Well-Known Biothreat Simulants, in Single-Cell Particles and Cell Clusters of Different Compositions

Assessing of Flexible Packaging Integrity: Using the Aerosolization Bacteria

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