Effect of Agar Plate Volume on Accuracy of Culturable Bioaerosol Impactors

Therkorn, Jennifer; Mainelis, Gediminas

doi:10.1080/02786826.2013.842954

Cited by 9 publications

(6 citation statements)

References 37 publications

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“…Two bacterial species were used throughout this study: Bacillus atrophaeus (ATCC 49337, Manassas, VA), a hardy, gram-positive bacterium representative of environmental species 43 , and Escherichia coli (ATCC, 15597), a sensitive, gram-negative bacterium representative of a species endogenous to the internal flora of the gut 44 , and prepared according to established protocols 45 . Briefly, active B. atrophaeus cultures were inoculated in Nutrient Broth (Thermo Scientific, CM0001B) and incubated at 30°C for 18 h; active E. coli cultures were inoculated in liquid Trypticase Soy Broth (Thermo Scientific, R455052) and incubated at 37°C for 18 h. Cells were harvested from microbial suspensions by centrifugation for five minutes at 7000 rpm (BR-4 centrifuge, Jouan, DEC Inc., Lorton, VA).…”

Section: Methodsmentioning

confidence: 99%

Inactivation of pure bacterial biofilms by impaction of aerosolized consumer products containing nanoparticulate metals

Therkorn

Calderon

Cartledge

et al. 2018

Environ. Sci.: Nano

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The ability of nanotechnology-enabled consumer sprays to inactivate bacteria has direct health implications. This research investigated the ability of six nanosilver-based consumer sprays to inactivate bacteria. We determined the minimal inhibitory concentrations (MICs) of the products by an agar dilution method, collected particles released from sprays onto bacterial films using impactors, and determined metal concentrations in the products using ICPMS. Also, the size of silver nanoparticles in the products' suspensions was determined using single particle (sp)ICPMS. Two of the six nanoproducts inhibited growth of and bacteria (MICs of 40,000 and 160,000 ppm). Collection of particles aerosolized from these two products onto films of the same bacteria inhibited bacterial growth; however, the mass concentration deposited onto bacterial films was lower than the MICs. Furthermore, these two nanoproducts had the lowest silver concentrations compared to the other four nanosilver products. Yet, they had the smallest nanosilver particles: mean size of ~20 to 30 nm vs. ~45 nm for the other products. Their suspensions were more acidic (pH ~3-5) and had higher concentrations of zinc and magnesium compared to other products. This research illustrates that some consumer nanoproducts have antibacterial potential and may affect our microbiota. Yet, the inactivation potential cannot solely be presumed based on the nanosilver presence and concentration in the product; the final nanoproduct's form, including its matrix, must be considered. As nanomaterials are increasingly incorporated into consumer goods, this research highlights the need to investigate final-form consumer nanoproducts and their potential to affect our microbial environment.

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Section: Methodsmentioning

confidence: 99%

Inactivation of pure bacterial biofilms by impaction of aerosolized consumer products containing nanoparticulate metals

Therkorn

Calderon

Cartledge

et al. 2018

Environ. Sci.: Nano

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“…1. To minimize the variations of the physical collection efficiency as mentioned in previous studies (Therkorn & Mainelis, 2013;Xu & Yao, 2011), a 90-mm(diameter) petri dish filled with 30 mL agar (achieving a jet-to-plate distance of 75 mm) was used for the sampling both for the HighBioTrap and the BioStage. The HighBioTrap sampler, about 1.9 kg, was designed based on particle inertia with a single "nozzle" (its physical characteristics along with other commercially available ones are listed in Table 1).…”

Section: Sampler Designmentioning

confidence: 99%

A high-flow portable biological aerosol trap (HighBioTrap) for rapid microbial detection

Chen

Yao

2018

Journal of Aerosol Science

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A B S T R A C TBioaerosols exposure can lead to many adverse health effects and even result in death if highly infectious agents involved. Apparently, there is a great need for rapid detection of bioaerosols, for which air sampling often is the first critical step. However, currently available samplers often either require an external power and/or with low sampling flow rate, thus falling short of providing a practical solution when response time is of great concern.Here, we have designed and evaluated a new portable high volume bioaerosol sampler named as HighBioTrap through optimizing its operating parameters. The sampler was operated at a sampling flow rate of 1200 L/min, with an impaction velocity of about 10.2 m/s (S/W = 1.5, T/ W = 1), while the weight of the sampler is about 1.9 kg. The performances of the HighBioTrap sampler were tested both in lab controlled and natural environments (outdoor and indoor environments in a university building) along with the reference sampler-the BioStage impactor using aerosolized Polystyrene (PS) uniform microspheres of various sizes, aerosolized bacteria and also ambient air particles. The microbial community structures of collected culturable bacterial aerosol particles both by the HighBioTrap and the BioStage impactor in the natural environments were analyzed using gene sequence method.Experimental results with PS particles showed the HighBioTrap has a cutoff size of~2 µm. The widely used impactor design equation was found to be not applicable for predicting the performance of the HighBioTrap due to its large Reynolds number. When sampling aerosolized individual Pseudomonas fluorescens and Bacillus subtilis bacterial particles, the HighBioTrap had physical collection efficiencies of 10% and 20%, respectively. Despite the higher desiccation effects introduced by higher flow rate, the HighBioTrap was shown to obtain a higher microbial diversity than the BioStage impactor for both in outdoor and indoor environments given the same sampling time (p < 0.01). Our data also showed that most of the desiccation effects might have occurred between 3 and 5 min of the sampling and an impaction velocity of around 10 m/s might be a close-to-optimal impaction velocity for collecting most environmental bacterial aerosols while maximally preserving their culturability. This work contributes to our understanding of microbial sampling stress (impaction velocity and sampling time), while developing a portable high volume sampler. The HighBioTrap sampler could find its great efficiencies in qualitative microbial aerosol detection and analysis, such as investigation of microbial aerosol diversity for a particular environment, or when the low level of pathogens is present and detection time is of great concern.

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“…Drawbacks may include loss of microbial cells viability due to impact stress and loss of recovery efficiency due to the failure of microbes to adhere to agar surfaces. Competition for growth and the influence of selective media choices should also be considered when planning a monitoring strategy [92]. Impaction is often the preferred active monitoring approach for bioaerosol sampling in the food processing environment.…”

Section: Available Sampling Methodsmentioning

confidence: 99%

“…The field is dominated by lack of consistent data and an abundance of speculation [7]. The lack of standard methods, environmental guidelines, and databases complicates the interpretation and comparison of results [92]. Also, since no single method can fully characterize all bioaerosols components [7], it is imperative to do a proper evaluation/investigation before choosing a sampling method or initiating a sampling protocol.…”

Section: Complications and Considerations Related To Bioaerosol Detecmentioning

confidence: 99%

Bioaerosols in the Food and Beverage Industry

Theisinger¹,

Smidt²

2017

Ideas and Applications Toward Sample Preparation for Food and Beverage Analysis

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Bioaerosol monitoring is a rapidly emerging area of industrial hygiene. Microbial roles in atmospheric processes are thought to be species specific and potentially depend on cell viability. Accumulating evidence suggests that exposure to bioaerosols may cause adverse health effects, including disease. Studies of bioaerosols have primarily focused on chemical composition and biological composition, and the negative effects thereof on ecosystems and human health have largely gone unnoticed. This gap can be attributed to international standards on acceptable maximum bioaerosol loads not being uniform and the lack of uniform standardized methods for collection and analysis of bacterial and fungal bioaerosols. In this chapter, bioaerosol composition, relevance of bioaerosols to the food processing facility, sampling and detection approaches, and complications were discussed.

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Effect of Agar Plate Volume on Accuracy of Culturable Bioaerosol Impactors

Abstract: . This effect may be attributable to sampler jet dissipation with lower nozzle number impactors (i.e., the Sampl'air) being more sensitive. This study demonstrates that bioaerosol impactor agar plate volume should be considered prior to sampling.

Cited by 9 publications

References 37 publications

Inactivation of pure bacterial biofilms by impaction of aerosolized consumer products containing nanoparticulate metals

Inactivation of pure bacterial biofilms by impaction of aerosolized consumer products containing nanoparticulate metals

A high-flow portable biological aerosol trap (HighBioTrap) for rapid microbial detection

Bioaerosols in the Food and Beverage Industry

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